Wash potatoes. Cook in boiling water to cover 15 minutes or until tender; drain and cool completely. Peel potatoes, and cut into 1/2-inch cubes. Combine potato, olives, and onion; stir gently.
Combine Ranch-style dressing and remaining ingredients in a small bowl; stir well. Add dressing mixture to potato mixture; toss gently to coat. Cover and chill.