Prepare Wish-Bone® Italian Dressing & Seasoning Mix according to package directions using red wine vinegar and olive oil. Reserve 2/3 cup Dressing & Seasoning Mix. Refrigerate remaining Dressing & Seasoning Mix.
Cover potatoes with water in large saucepan; add salt, if desired. Bring to a boil over high heat. Reduce heat to low and simmer uncovered until potatoes are tender, about 8 minutes. Drain and set aside.
Combine reserved Dressing & Seasoning Mix, mayonnaise and parsley in large bowl; stir in red pepper, celery and onion. Add potatoes; toss gently. Season, if desired, with ground black pepper. Serve chilled or at room temperature.