dumplings in oahu?
A really great place to check out is a small little shop in Chinatown that only makes manapua (steamed buns with pork or sweet black beans), and various kinds of dumplings.
Check out Char Hung Sut Manapua at 64 N. Pauahi Street. They close when they sell out, so go early in the morning.
I would try one of everything and figure out what you like best. Good luck!