1. Drain and reserve syrup from pineapple. Cut each pineapple slice in half; set aside. In medium-sized bowl, mix brown sugar, water, cornstarch, vinegar, horseradish, and reserved syrup from pineapple; set mixture aside.
2. Cut pork-sausage meat into 1/4-inch slices. With sharp knife, make a few slashes in each cocktail frankfurter.
3. In 12-inch skillet over medium heat, cook sausage slices, a few at a time, until well browned, removing slices as they brown to paper towels to drain well; keep warm. Pour off fat from skillet.
4. In same 12-inch skillet, over medium heat, cook frankfurters until lightly browned; add reserved pineapple slices and return sausage slices to skillet. Gradually stir in reserved pineapple-syrup mixture and cook about 5 minutes, stirring frequently, until sauce thickens slightly and mixture is heated through. If you like, serve sausage mixture in chafing dish to keep it warm.