Kona Cafe is located upstairs in the Great Ceremonial House of the Polynesian resort. Here you can sit down for a restaurant meal, but feel free to ask for the sushi menu from the bar adjacent. The feel of the restaurant and the menu is Asian infused American dishes and the food is delicious. Kona Cafe currently participates in the Disney Dining Plan for 1 TS credit. Check out the menus and see for yourself:
Also, Kona Island located near the monorail stop is also a quick stop for some coffee (Kona of course) in the morning, and a sushi bar in the afternoon/evenings.