Spray skillet with cooking spray. Saute beef and remove. Saute onion and garlic in skillet until tender. Add pepper and a small amount of water to onion and garlic; cover and cook on low until tender. Sprinkle with boullion granules and add teriyaki sauce and two third c water. In a measuring cup, make a paste with the quarter cup hot water and cornstarch. Pour into the skillet and cook for a few minutes until thick. Add tomato and cook until tender. Serve over hot cooked rice.