Mix thoroughly beef, crumbs, onion, egg, salt, ginger and milk. Shape mixture by rounded tablespoonfuls into balls. Melt shortening in large skillet; brown and cook meatballs. Remove meatballs; keep warm. Pour fat from skillet.
Mix cornstarch and sugar. Stir in reserved pineapple syrup, vinegar and soy sauce until smooth. Poor into skillet; cook over medium heat, stirring constantly, until mixture thickens and boils. Boil and stir 1 minute. Add meatballs, pineapple tidbits and green pepper; heat through.