Cook fusilli according to package directions. Drain and rinse with cold water until cool.
Combine Hellmann's® or Best Foods® Real Mayonnaise, vinegar, olive oil, oregano and brown sugar in large bowl. Stir in cucumber, onion, tomatoes and olives. Add fusilli and spinach; toss. Top with feta.
*Substitution: Use 1 tsp. dried oregano leaves, crushed.