What type of food are you looking for? Just about 10 minutes north of KMG by taxi is an area with lots of restaurants that do wild mushrooms hot pots, and that's what many people from HK do when transiting KMG. But not sure if you're interested in those.

A bit more mainstream is a place for "Cross Bridge Rice Noodles" (过桥米线) that's attached to the Wal-Mart, also about 10 minutes north of airport by taxi. Easy to find. Huge bowl of rice noodles, with like 20 ingredients that they put into your bowl right at your table. And inexpensive.