li hing anything, starting with fresh pineapple, dried mango, and candies you already like, such as sour patch kids, gummy bears, apple rings, sour apples, rock candy (my fave) etc. li hing candies, li hing dried fruit, and li hing powder available at longs drugs/cvs. get the powder and put on fresh pineapple, shots of tequila, etc. it is an incomparable taste. if you dig it, you can try more hardcore 'crackseed' treats.
a loco moco is a good place to start as well. ingredients found anywhere: rice, hamburger patty, eggs, brown gravy (some places use a diff gravy like a creamy mushroom; i think a beefy brown is the best), onions if you like. try the one at liliha bakery. a lot of mainlanders get weirded out by the combo, but it seems like a burger with rice instead of bread to me. a lot of other mainlanders like it quite a bit. you decide.
As has been asked:
What do you want?
What is your budget?
Where are you staying?
Do you have an auto?
O`ahu is a food paradise (no pun intended), and we try to build in several days there, regardless of where else we might be visiting. I could recommend a dozen restaurants, but those might not be what you are looking for.
Of all the Island, and the sides of the Islands, O`ahu, and Honolulu/Waikiki has the greatest, and most diverse wealth of restaurants. However, those range from good, but low-end mom-n-pops, to some stellar high-end dining.
Help us, to help you.