Preparation Stir pineapple juice, soy sauce, cornstarch, and vinegar in small bowl until cornstarch dissolves. Heat oil in heavy large skillet over high heat. Add green onions, garlic, ginger, and chili and stir 1 minute. Add scallops, red bell peppers, and bok choy to skillet. Stir-fry until scallops are almost cooked through, about 4 minutes. Stir cornstarch mixture to reblend and add to skillet. Stir until sauce comes to boil and thickens and vegetables and scallops are cooked through, about 1 minute. Season with salt and pepper.