Not in any meaningful sense. It is possible that some of the ancestors of the modern Kurds already lived in the regions crossed by the Ten Thousand on their retreat from Mesopotamia. However, they are not present in his text, and do not make an appearance in any other evidence of the period. There is no trace of a Kurdish identity at this time. The Iranian word "Kurd" is first used in a Sassanian epic which may date as late as the 7th century AD - more than a thousand years after the March of the Ten Thousand.

After the Greek mercenaries of the Ten Thousand were driven out of Mesopotamia, they made their way through the territories of the Karduchians, Chaldaians, Armenians, Taochians, Chalybians, Makronians and Kolchians. None of these peoples controlled more than a fraction of the region inhabited by the Kurdish people today. None of their names are etymologically related to the Kurds. The only ancient people of this general region who may have been at the origin of "Kurd" are the Kyrtians, but these are not among the peoples encountered by Xenophon; they are first recorded 180 years later. And even then, the linguistic link is disputed.

So where does the idea come from that Xenophon encountered the Kurds? Mainly it is the projection of a modern identity onto Xenophon's description of the Karduchians, the first people the Greeks encountered as they left the plain:

The route through the mountains and northward led to the country of the Karduchians. These Karduchians, they said, dwelt up among the mountains, were a warlike people, and were not subjects of the King; in fact, a royal army of one hundred and twenty thousand men had once invaded them, and, by reason of the ruggedness of the country, not a man of all that number came back. Still, whenever they made a treaty with the satrap in the plain, some of the people of the plain did have dealings with the Karduchians and some of the Karduchians with them.

-- Xenophon, Anabasis 3.5.15-16

The location of this autonomous people is convenient: the Ten Thousand would be marching through what is now Northern Iraq into what is now southeastern Turkey. This is the heartland of the modern Kurdish people. The name Karduchoi is at least close enough for willing minds to see a link with the Kurds. And of course their fierce independent spirit and affinity with their mountainous homeland will sound recognisable to many.

But this is special pleading. The notion that the Karduchians are the Kurds relies on the idea that these people have always lived in the exact same place, have never moved, and have never absorbed any meaningful influence from outside - even though the region was part of many large empires that habitually moved populations around to control them more easily. As John Limbert pointed out long ago (Iranian Studies 1.2 (1968), 41-51), the description of these mountain people as hardy, warlike and independent is generic, and many other peoples in the area could have been described in the same way. Morever, the link with the Karduchians is not the story that the Kurds historically told about themselves. They claimed that they descended from Medes, not Karduchians. We should at least admit that there is not much solid ground here, and we should probably concede that the identification is not very likely.

The problem here is the sheer width of the chronological gap between the earliest mentions of supposed "Kurds" and the confirmed presence of Kurds as an identifiable ethnic group in the historical record. Where there is so little evidence, theorising is easy, and theories are difficult to disprove. Modern readers can be inspired by the passage from Xenophon and feel that the Karduchians must be a sort of proto-Kurdish people living in a once-and-future Kurdistan; there's not much anyone can do to disabuse them of the idea.

The only thing I feel might be worth mentioning here is that the Karduchians of Xenophon's account might not be the finest people to identify with. Xenophon writes that they rejected all Greek attempts to parley with them, even though they shared a common enemy (An. 4.1.8-9), that they would leave the main marching column alone and only attack the Greek rearguard (4.1.10-22) and that they refused to meet the Greeks in hand-to-hand combat (4.2.7-8, 15). While they caused the rearguard significant distress and inflicted quite a few losses, Xenophon does not single them out for special praise; it is the Chalybians he described as the bravest of all the peoples he encountered (4.7.15). It is quite likely that he played up the threat and described the skirmishing in detail because Xenophon himself commanded the rearguard, and bore the brunt of the fighting in Karduchian territory.