To prepare dressing, combine first 6 ingredients, stirring with a whisk.
To prepare salad, cook pasta in boiling water 6 minutes or until al dente. Add bell peppers to pasta in pan; cook 10 seconds. Drain. Combine pasta mixture and half of dressing in a large bowl; cool mixture to room temperature. Add remaining dressing, tomato, and remaining ingredients; toss gently to coat. Cover and chill at least 1 hour.