@MaybeBabyMustache, one quick and dirty indicator I use to check how large the Asian population is in a given area is to do a search for Asian markets. Places with a large Asian population will not only have lots of them, there will also be many that specialize in a particular subregion. The greater Seattle area now has many different Chinese, Vietnamese, Japanese (if you consider Uwajimaya's roots -- they are really pan-asian at this point), Korean, and Indian markets, plus some smaller ones for things like Filipino and Cambodian/Lao/Thai, etc. They are also spread around the region pretty liberally, unlike 30 years ago when you basically had to make a trip to the International District in Seattle to find them.
Looks like Boise has a few, mostly general pan-Asian. No H-Mart yet:
https://www.yelp.com/search?find_desc=Asian+Grocery+Stores&find_loc=Boise%2C+IDBend doesn't seem to have any.
You can do a similar search for other cuisines to check for other types of diversity.
Makes me miss my old neighborhood in NYC where we were a couple of blocks away from every type of regional subspecialty you could want....