If they were paying attention, but of course that's a big if.

There is record, for instance, of Hitler haranguing Chancellor Bruning in a private meeting in 1930 to the effect that he would annihilate Germany's enemies including France. Contrast with Bruning's position at this meeting that he would negotiate with the western allies to secure breathing room. Bruning was mostly despised at this time, while Hitler had just made his first electoral breakthrough. If it were of any great concern to the German people, one can easily see this statement being put to political use by Bruning or one of the other politicians in the room at the time. Hitler was making no secret of it to them. Nor did he make any secret of it in Mein Kampf, which goes on at length about fighting wars of annihilation against Germany's foreign enemies.

Of course, in his oratorical plays for populist support he would not have said such a thing. No one at that time would have believed Germany capable of defeating France. To threaten France with war in 1930 would not have seemed patriotic, it would have seemed delusional. Most probably saw the rhetoric about lebensraum as aspirational, and while there were many who saw through the ploy and who understood the risks, including writers and politicians, they lost any sort of real audience after 1933.

Such a perceptive observer would have seen not just the ramblings of Mein Kampf but also the thuggery, the street violence. They would have surmised from the glorification of combat and violence that Hitler's was a political style that could develop into something much more dangerous. They would have understood the connections to the world that broke out into World War One. If your followers demand violence eventually you must serve it up on someone or risk having the violence turned on you. Hitler navigated this tension by slowly dialing up the diplomatic bluster so that he could simultaneously seem like the man of peace, of which he was able to convince the British for several years, and the man to restore Germany's honor.

And, probably, most Germans did not consciously want a war. The horror of World War One was very much alive in memory. The journalist William Shirer, who is problematic in some of his analyses but who did get to see the opening days of the war at first hand, reports of the first morning of war with Poland:

There was no such demonstrations [as greeted the opening of World War One] this time for the troops or for the Nazi warlord...even the robot members of the Reichstag, party hacks, for the most part, whom Hitler had appointed, failed to respond with much enthusiasm as the dictator launched into his explanation...There was far less cheering than on previous and less important occasions when the Leader had declaimed from his tribune.

Even most of the high staff had argued vigorously, not just against war with Poland, but against Anschluss and the annexation of the Czech Republic. Hitler was forced to act very quickly to secure some victories. It was triumph over France that brought the true war fever.

This discussion could obviously fill a long book, so please do ask a follow up question if you like.

Quick edit to dispel any confusion (I feel like my net has a wide mesh): Many people did not vote for Hitler and many of those understood the implications of Nazism. They need only look back at the preceding two generations to see the potential for the German people to be herded into wars of aggression. I took the question to mean that, of the large masses of people who did vote for the Nazis in 1932, how many were voting for war? My answer is, probably not very many outside of the SA and the diehards. From the very start and indeed throughout the 30's, Hitler made a very plausible (to the average person) case that he desired peace. The merest handful of fever dreaming fanatics would ever have foreseen not just war but a war on the scale it was fought.

Sources:

Kerhsaw's Hitler

Shirer's Rise and Fall of the Third Reich

George Mosse's Masses and Man

Wow that's quite a question. I'll do my best here, but keep in mind that there are entire rows, minimum, in libraries devoted to more or less this topic. I will by no means answer every aspect of this, so I await people to add on to what I've written (please don't engage me in opinion-based debates though).

The first thing you have to keep in mind is that very few people were invested in/proud of the Weimar Republic. It was a concession government born in a haphazard 'revolution' on the heels of a devastating and embarrassing loss in World War I.

The second thing you have to keep in mind is that not that many people actually ever voted for the Nazi party in free elections - in July '32 they won 37% percent of the vote for the Reichstag (parliament). This was certainly the most of any party, BUT not like 89% or whatever you might guess if you didn't know much about the period.

Next, and this is a huge one: THE WORLD HATED COMMUNISM. Germany was no exception. One thing that led the conservative establishment to accept the Nazis, as well as the populace, was that they literally fought the communists on the streets. Many intellectuals saw National Socialism as an escape from the horrors of communism and western capitalism/liberal democracy (which were seen very much in the same light).

Fourth, the country was extremely embarrassed by World War I. And they were, in their view, still being oppressed by the result of it. Put quite simply - many Germans did not necessarily think that continuing the war was such a bad idea. Perhaps for many of the rest, they were not about to go to metaphorical war to avoid going to actual war, if that makes sense.

Now, finally, as for whether or not people voting knew the vote could lead to war: The biggest thing here is that they did not vote Hitler as Chancellor. That decision was made by President von Hindenburg in January 1933. Of course the popularity of the Nazis had much to do with his decision. Still, keep in mind: Hitler's party was voted into a significant number of seats in 1932 by the German people; it wasn't a decision to make him dictator (after all, they still functioned within the framework of a democracy).

Another huge factor: the Nazis were most popular in trying times. In the 'Golden Years' of Weimar, they lost significantly in popularity. After the Great Depression hit, they gained traction again. Nonetheless, while many people bought into their message, they didn't necessarily (or in most cases definitely did not) agree with the obvious anti-Semitism and war-mongering. Most assumed, somewhat reasonably, that the Nazis would be an energizing force in a lackluster and ineffective government. (Boy were they wrong.)

I'm very glad you brought up the SPD and KPD (social democrats and communists). They were very much anti-Nazi. They were also very different parties. In fact, they fought each other intensely during these elections, and the fact that they didn't unite against the Nazis, in retrospect after the war, was their crucifixion. But in the early '30s, you have to remember that communism was fighting for its life, not to mention the 'global communist revolution.' The KPD (comm's) saw the SPD as worse, in many ways, than the capitalist stooges because they lured people into thinking that they could have a 'half-revolution' without sacrificing too much. This was contrary to their thinking. The SPD, on the other hand, was very much into the ideals of social democracy, but saw communism for the totalitarianism and false utopia that it turned out to be. Put briefly, those parties WERE NOT ALIGNED.

Realizing that wasn't exactly your question (though very important to keep in mind) I come to the question of whether they sought to expand German influence. I'll admit I haven't read as much about those parties' platforms, but the KPD was essentially an organ of Moscow even at that point. They took pointers from the USSR about bringing about a communist revolution in Germany. So in that sense, they did not promote German nationalism in the way that the Nazis did (which is not to say that communism was intended to be the death of culture; Stalin himself was basically an expert on Georgian culture for the Bolsheviks in his earliest involvement with the party). The SPD was a liberal democratic party. They were not interested in starting World War II. I encourage you to read more about them, in particular, because again I don't have a lot of expertise about the SPD in the early '30s specifically.

As for your follow-up question. Certainly many intellectuals saw the Nazis for what they were, and many people were very turned off (as mentioned earlier) by their violence, anti-Semitism, and general unpleasantness (they were seen as idiots and thugs, for the most part). The Nazis were not especially well-regarded as such by intellectuals and the elite, so most didn't see the need to spread such wide propaganda. I'm sure you could go back and find anti-Nazi propaganda around 1930, but it probably did not seem all that necessary to elites at the time. They weren't living in 21st century America, so they didn't respect (and fear) the power that voting could have.

Well, I will probably think of 10 more things in the next hour that I could have said, but those are some of the main elements in this issue.

Sources. Here are some of the best authors for these topics: Kershaw (Hitler books), Koonz (Nazi Conscience), Herf (Reactionary Modernism), von Klemperer (Germany's new conservatism), Mosse (Crisis of German ideology; Germans and Jews), Broszat (The Hitler state), von der Goltz (Hindenburg book), Paxton (Anatomy of fascism). That's a good start.

Follow up - within Germany, were there any largely publicized efforts to paint the Nazis as war mongers?