All the islands have first-class restaurants, many with celebrity chefs reinventing pan Pacific cuisine. But if you want to save a boatload of money and eat at a restaurant with unmatched views and atmosphere, not to mention unlimited seating, then make like a Hawaiian and head for the beach.
For the menu selections, head for a Hawaiian plate lunch restaurant— L&L is a popular chain, but every town will have its locally owned offerings. For well under ten bucks, you'll get a meat or seafood selection, with a starchy side dish of rice or Hawaiian potato-mac salad. The leaning is teriyaki, but plate lunches reflect Hawaii's "calabash" of cultures. The first Hawaiian settlers brought food and cooking techniques with them from Polynesia, while Japanese, Chinese, Filipino and Portuguese immigrants have since each contributed their own culinary sensibilities.
Another option is a supermarket, like Foodland or Big Save, where bargain-priced sushi selections are prepared fresh and ready to go.
Then get to the beach before the sun goes down. Kihei on Maui has a number of plate lunch places with the three Kamaole Beach Parks nearby. On Kauai, head for Hanalei Bay after picking up dinner in town a few blocks away. Hilo on the Big Island has excellent take-out options and a huge beachfront park on Hilo Bay. On Oahu, the offerings are numerous near Waikiki Beach—but why huddle at a table when you can head for Kuhio Beach Park and dine in the sea breeze with the nightly free hula show as entertainment?