1.In A 3-Qt. Slow Cooker, Combine The First Eight Ingredients. Add The Ribs, Tomato And Onion. Cover And Cook On Low For 4-5 Hours Or Until Meat Is Tender. 2.In A Small Bowl, Combine Cornstarch And Cold Water Until Smooth; Gradually Stir Into Cooking Juices. Cover And Cook For 10-15 Minutes Or Until Thickened.