Cook rotini to desired doneness as directed on package.
Meanwhile, in large bowl, combine zucchini, tomatoes, mushrooms and onion; mix gently.
Drain rotini; rinse with cold water. Drain well. Add to zucchini mixture.
In blender container, combine all dressing ingredients; blend until well mixed. Pour over salad; toss gently. Serve immediately, or cover and refrigerate until serving time. If desired, garnish with fresh basil leaves and grated Parmesan cheese.