Place potatoes in 8"x8" microwave-safe dish; cover with vented plastic wrap. Microwave on high for 4-6 minutes or until potatoes are just tender, stirring once. Cool slightly. Cut beef steak into 1-1/4-inch pieces. Alternately thread beef and vegetables onto eight 9-inch metal skewers. Brush kabobs with 4 tablespoons dressing; reserve 2 tablespoons. Place kabobs on grill over medium, ash-covered coals. Grill, uncovered, for about 10-12 minutes for medium rare to medium doneness, turning occasionally. Season with salt and pepper, as desired. Drizzle kabobs with remaining 2 tablespoons dressing before serving medium-rare.