Cook pasta as directed on package, omit salt. Drain. Cool
Mix dressing and mayo in medium bowl. Add to pasta and onions; toss to coat.
Gently stir in fruit. Refrigerate for 1 hour.
NOTE: If wishing to prepare more than 1 hour in advance, combine dressing, mayo, cooked pasta and onions in large bowl. Combine oranges and strawberries in separate bowl. Refrigerate up to 8 hours. Add fruit to pasta mixture up to 1 hour before serving. Keep refrigerated.