In a saucepan, bring 2 inches of water to a boil. Add beans,sugar snap peas, yellow squash, zucchini and onion. Reduce heat; cover and simmer for 2-3 minutes or until vegetables are crisp-tender. Drain. Rinse with cold water and pat dry.
Place vegetables in a bowl. Add remaining ingredients. Gently stir to coat. Refrigerate until serving.