Heat oven to 400 degrees F. Whisk together dressing, lemon juice, horseradish and chili powder in liquid measure.
Alternately thread green pepper, mushroom halves, tomatoes and meatballs on 4 metal skewers, dividing evenly. Place skewers on foil-lined broiler pan.
Bake in preheated 400 degree F oven, turning skewers occasionally, for 20 to 25 minutes or until vegetables are tender-crisp and meatballs are heated through. After 10 minutes of cooking, brush all sides of kabobs with dressing mixture. When finally cooked, brush with remaining dressing. Serve over rice if using. Makes 4 servings.