In a large bowl, combine the first 6 ingredients. Crumble beef over mixture and mix well. Shape into 1-1/4-in. balls. Place meatballs on a greased rack in a shallow baking sheet. Bake at 450° for 15 minutes. Drain on paper towels.
Meanwhile, for sauce, combine the tomatoes, brown sugar, vinegar, salt and onion in large saucepan. Bring to a boil. Stir in gingersnaps, continuing to boil until sauce is thick and clear. Reduce heat to simmer; add meatballs. Heat through.