Mix dressing ingredients and refrigerate overnight.
Cook rainbow rotini till almost soft. Do not over cook since it will soak up dressing and get soft. Drain rotini and cool. Dice up tomatoes. Deseed and dice up cucumbers. Chop onion or use cut up green onions. Chop broccoli up stem and all into small pieces.
Toss cooled pasta with all vegetables and pour dressing over top and mix well. Serve cool.