I have heard that the Ruric dynasty of Kievan Rus were vikings, how true is that?

I have heard that the Ruric dynasty of Kievan Rus were vikings, how true is that?

I guess it comes down to how you define "Vikings" because the origins of Rurik are fuzzy at best. According to the Primary Chronicle "They accordingly went overseas to the Varangian Rus", this could imply sailing west to Sweden or Denmark, however, it could also imply sailing north to Finland. Rurik appears to have belonged to Y-DNA haplogroup N1c1 which is fairly rare in Scandinavia but fairly common (these days) among the Swedish speaking population of Finland.

So what does it tell us? Well, that he probably belonged to the group that today primarily populate the costal areas of Finland. That doesn't mean that he can't have been from Scandinavia, it just makes it less likely, N1c1 exists in Scandinavia too and the group may well have originated (locally) in present day Sweden. Archeological finds in the area suggest a considerable scandinavian influence among the ruling classes until at least the 10th century.

The origins of the Rus' people has been a topic of some debate, occasionally one that has been smudged by various nationalist sentiments in Russia and the Ukraine. There are three main views here:

The Normanist View
Basically states that the early Rus' were probably Vikings from the area around Uppsala who settled in the east. There are numerous runestones still on display today that tell relatively detailed accounts of the journeys and settlements in the east. The genetic evidence and the Primary Chronicle also support this view, so does the early names of the line of Rurik and "neutral" accounts by arab and byzantian travelers who describe the Varangians/Rus' as tall and blonde with clothing and weaponry consistent with what we know about 9th-10th century Vikings. There is also a Byzantian account of two Rus' guards in Constantinople who, upon being asked where they're from, answer "Sweden".

The anti-Normanist View
Basically a variety of different explanations for who the Rus' were, much of this scholarship is questionable and strongly linked to various nationalist movements all attempting to prove that the Rus' culture originated in a specific present day country. There are some meritous points within it however, notably the lack of Scandinavian influence on the Russian language and the lack of cultural influence. The Vikings in History by F. Donald Logan states that "...in 839, the Rus' were Swedes. In 1043, the Rus' were Slavs." This suggest that while they may originally have been Swedish they were relatively quickly integrated into the Slav society and left few cultural traces.

The non-Normanist/non-anti-Normanist view
The third possibility is that neither previous version is entirely true but that elements of both are true. The early Rus' may not have been an ethnically uniform group at all but a collective term for various ethnic groups that traveled, traded and plundered in the region but hailed from Sweden, Finnland and Slavic lands. It is quite possible that the reason the Swedes stood out more than the other groups was simply because their physical appearance was further from the other groups and that Uppsala was, at the time, possibly the most important location in the Baltic region.

I know this doesn't quite answer your question but it's probably the most accurate answer I can give you.

Also, did early Russian states had any other contact with Scandinavians?

Yes, absolutely. We know for a fact that early scandinavians inhabited the Ladoga area and traded with the Kievan Rus' with Furs. There was also fairly regular contact between proto-Russian states and Scandinavia from the Iron Age and onwards, increasingly so as the trade to Greece and Constantinople opened up.

EDIT: I left out the Rorik of Dorestad theory and some of the wilder nationalistic views proposed from various sides because I have seen little compelling evidence for them.