Separate the white from the green part of the scallion. Mince both white and green, but keep separate. Mix together the white of the scallion, ginger, catsup, chili sauce, sherry, soy sauce, sugar.
Heat the oil in a wok. Brown the garlic and discard it. Add shrimp and stir until the color has just begun to change. Stir in the above mixed ingredients. Mix well. Stir in the salt and red pepper. Stir until the shrimp are done. Serve hot, garnished with the green part of the scallion.