Cook pasta according to package directions, drain.
Place pasta in deep bowl.
Toss with tomato, onion, and beans.
Cut bell peppers into thirds; discard seeds.
Preheat grill over medium-high heat.
Brush peppers lightly with oil.
Grill 1/2 minutes per side.
Peppers will begin to char.
Slice peppers into thin strips.
Add to pasta dish.
Add all remaining ingredients, except yogurt, to pasta salad.
Toss salad with yogurt.
Divide salad onto serving dishes