Slice the  pineapple in half lengthwise. Remove fruit of pineapple and set shells aside. Remove and discard core and cut pineapple into 1" chunks. Set aside Combine scallions, garlic, ginger, pepper, okra, soy sauce and sherry or rice wine vinegar in a wok. Stir-fry over high heat until vegetables are tender crisp about 4 minutes. Add one teaspoon of water if vegetables appear to be sticking. Add pineapple chunks, cover and continue cooking for 3 minutes. Spoon into pineapple shells and serve immediately.