Mama's Fish House serves lunch and dinner daily but it was the pupu that got HONOLULU's dining columnist hooked. As we were watching plate after plate of crab cakes march out of the kitchen, not one but two waiters leaned in to whisper that the Seared Beef Polynesian ($18) was their favorite. Boy, were we glad we took the hint. Bite-size strips of warm, peppery beef come tossed with tomato, cucumber and Maui onion in mouth-puckering lime juice and garlic, all served in a grilled ripe papaya. Lunch is daily, from 11 a.m. to 2 p.m., a light menu from 2:15 to 4:15 p.m., and dinner from 4:15 to 9:15.