Preheat the oven to 400 degrees. Puree one 14-ounce can whole tomatoes; 1 garlic clove, roasted; 1 teaspoon olive oil; 1/4 teaspoon salt; and 1/4 teaspoon red pepper flakes. Set sauce aside. Heat 1/2 teaspoon olive oil in a medium skillet. Cut two 1/2-inch-thick slices lengthwise from a zucchini. Saute the slices with 1 garlic clove, minced, for 2 minutes on each side, until tender. Remove from skillet. Saute 1 cup sliced cremini mushrooms with a pinch salt for 3 minutes; set aside. In a small baking dish, layer 1/2 cup sauce, 1 slice cooked zucchini, 1/3 cup part-skim ricotta, 1 tablespoon shredded part-skim mozzarella, and mushrooms. Repeat with remaining zucchini slice, 1/3 cup part-skim ricotta, 1/2 cup sauce, and 1 tablespoon shredded part-skim mozzarella. Bake 15 minutes.