Preheat broiler. Lightly grease baking sheet. Cut polenta in 12 slices. Place polenta and zucchini on baking sheet. Brush with oil; sprinkle with salt and pepper. Broil 4 to 5 inches from heat for 8 to 10 minutes, until polenta is lightly browned and zucchini is crisp-tender; turning once.
Meanwhile, in large skillet cook and break up sausage over medium heat until sausage begins to brown. Drain off fat. Add mushrooms, tomatoes, and seasoning to skillet; cook for 5 minutes, until meat is no longer pink. Slice zucchini crosswise. Spoon sausage mixture and zucchini over polenta. Sprinkle with cheese. Makes 4 servings.