In a small container, stir the rice vinegar, soy sauce, sugar, and pepper. Reserve

Heat a pan over medium-high. Put some oil and add the garlic and ginger. Stir and let cook for 30 seconds and add the scallops. Cook for a minute then add the sauce

Reduce heat to low, flip the scallops, and let cook for another 90 seconds or so. If it looks dry add the water. Add the green onion. Turn heat off and serve.