Heat 1 tablespoon oil in large saucepan over medium-high heat. Add mushrooms and onion; cook 5 minutes or until tender, stirring occasionally. Stir in undrained tomatoes, sauce, vinegar and 1/4 teaspoon garlic salt. Bring to a boil. Reduce heat; simmer 10 minutes, stirring occasionally.
Meanwhile, carefully cut zucchini lengthwise into long thin noodles with vegetable peeler, stopping when seeds are visible. Discard center portion of zucchini.
Heat remaining 1 tablespoon oil in large skillet over medium-high heat. Add zucchini noodles and remaining 1/4 teaspoon garlic salt; cook 5 minutes or until desired doneness, stirring occasionally. Serve zucchini noodles with sauce. Top with cheese, if desired.