The guesthouses in Auki are the main places to eat, and most will prepare meals for guests with advance notice. The food leans on local staples: fresh fish from the morning market, taro and sweet potato, rice, and greens cooked in coconut milk. Quality varies but the ingredients are good, especially the fish — reef species like parrotfish and snapper come in fresh daily, and barracuda is a regular catch.
There are also a few small trade store canteens around the market area serving rice-based dishes during the day. These are no-frills operations — plastic chairs, fluorescent lighting, a limited choice — but the food is filling and cheap, and you will usually be eating alongside market vendors and government workers. The market itself is the best place to buy fresh produce if you are staying somewhere with cooking facilities.