The best local food that we have here in Phoenix that relatively few other cities have is our "taco trucks", kind of like regular food trucks only they sell, well, tacos and other mexican food. Finding them, though, is kind of a crap shoot, since, being mobile, they move around a lot to avoid zoning restrictions. They show up at local street fairs and other events, mainly downtown, and some can be found in fairly questionable parts of the urban core. I've found the food ranges from "meh, nothing special" to "pretty danged good", but what can you expect, it's a food truck. Most people have lower expectations of them, but they come away surprised at the quality many times.
