Discussion HERE with other links, including THIS
Actually, the Zunis do not resemble the Japanese, so I am skeptical about this...although the Chinese and others did manage to get to the Western coast of the Americas and may have left behind some technology (and babies) one suspects that the Zunis, like the other pueblo tribes, did not have to be taught everything from "superior" cultures...
But since I am not acquainted with pre colombian trade routes, I might be wrong...