Cook pasta according to package directions. In a small saucepan, combine cornstarch and water until smooth. Bring to a boil; cook and stir for 1-2 minutes or until thickened. Remove from the heat; stir in the Parmesan cheese, vinegar, oil, oregano, salt, garlic powder and pepper. Drain pasta; rinse in cold water
In a large bowl, combine the remaining ingredients. Add pasta and dressing; toss to coat. Cover and refrigerate for at least 1 hour before serving. Yield: 7 servings.