1. Bring 3 cups water to a boil in large saucepan over high heat. Add potatoes; return to a boil. Reduce heat to medium-low. Simmer, covered, 8 minutes. Add asparagus and bell peppers; return to a boil over high heat. Reduce heat to medium-low. Simmer, covered, about 3 minutes or until potatoes are just tender and asparagus and bell peppers are tender-crisp. Drain.
2. Meanwhile, combine yogurt, green onions, olives, basil, thyme, vinegar, sugar and ground red pepper in large bowl. Add vegetables; toss to combine. Refrigerate, covered, until well chilled.