Cut sausage in half lengthwise, then into 1/2-in. slices; brown in a large skillet over medium heat. Drain. Add the zucchini, tomatoes, onion, lemon juice, oregano, salt and hot pepper sauce if desired. Cook for 15 minutes or until zucchini is just crisp-tender. Sprinkle with flour; toss to coat. Bring to a boil; boil and stir for 2 minutes. Sprinkle with cheese. Remove from the heat; cover and let stand until cheese is melted.