Beat the egg in a small bowl. In another bowl, combine the ground pork, water chestnuts, scallion, cornstarch, sugar, sherry, soy sauce, the beaten egg and salt to taste. Stir until it becomes a paste.
Form into 1-inch meatballs.
Heat the vegetable oil into the wok over high heat until candy thermometer reads 375 degrees. Fry each meatball until the outside is golden and inside is no longer pink, about 3 minutes on each side. Drain well in a colander and serve.