mostly full of Vietnamese- Americans? It does not bother me, but it is just something I wonder about. Are most of the salons owned by Vietnamese? They always do an awesome job and I am so glad they are here, just wondering?
Perhaps there was immigration in your area, but I don't think it's true of all of the US. Many were refugees and were relocated to countries like the US and the UK and set up businesses. Many also have beauty and hair salons as they are pursing a trade they know. I don't think you can judge just by what you have seen, because in New York they have Chinatown, Koreatown etc and they all cater to the local community and anyone else that wants to visit.
I don't think you are entirely incorrect in terms of it being an area that has attracted them. In fact I think both of the comments above are correct to some degree. I'm from the UK and I've lived in the US, and I have seen similar dynamics in both places from both the Vietnamese, Thai and Filipino communities. Initially, I think it was a way that women from these communities were able to set up their own businesses in new countries. From there it became self perpetuating. But in terms of "mostly full of", I think that's not quite correct.
It is interesting that so many do nails because in many parts of Aisa it is very offensive to use ones feet to point or do anything. However, many businesses began as a family enterprise that resulted in more jobs for future immigrants. I think it happened without them realizing. While the part of the body must be ironic for some, I do feel the Asian culture as a whole is very good at taking care of themselves. They never look disheveled to me. Stereotypes are never true as a whole, but I do think they excel in stream lining.