COMBINE vinegar, oil, mustard, salt and pepper in container with tight-fitting lid. Shake well.
COOK potatoes in salted water just until tender, about 15 to 20 minutes. Drain. Cool 10 minutes. Cut into bite-size pieces.
COMBINE cooked potatoes with carrots, celery, onions, radishes and tomatoes in large salad bowl.
SHAKE dressing. Pour over salad. Toss to mix well. Serve immediately or refrigerate. Top with tomato wedges, if desired.
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*Percent Daily Values are based on a 2,000 calorie diet