Cook pasta according to package directions. For last 2 minutes of cooking, add broccoli florets. Drain noodles and broccoli. Rinse immediately with ice cold water.
In a large bowl, combine the pasta and broccoli with the tuna and other vegetables.
In a small bowl, mix dressing ingredients. Beat with a whisk for a creamy-textured dressing.
Just before serving, pour dressing over tuna-pasta salad and mix well. 6 servings.