Combine pork, sugar, 2 tablespoon soy sauce, ginger and garlic. Mix well and let stand 15 mins.
Heat 12-inch skillet and add 1 tablespoon oil. Add pork mixture and stir-fry approximately 3 minutes. Remove from skillet. Add remaining oil and stir-fry peppers and onions for 3 minutes or until crisp-tender.
In a small bowl combine pineapple liquid, cornstarch mixture. Cook until sauce has thickened and pineapple is thoroughly heated, stirring constantly.