If using cooked left over pork, trim excess fat and cut into 1" chunks. Place in a large fry pan. No need to heat.

Prepare sauce by combining all ingredients, except cornstarch in water, in a medium saucepan. Bring to a boil and simmer 1 minute. Slowly add cornstarch and water mixture and stir and cook until thickened. Add green pepper to sauce and cook 1 minute.

Transfer sauce mixture to fry pan with meat. Add tomato, pineapple and mandarin oranges and heat through. Serve over rice.