PREHEAT oven to 425°F. Beat dressing and mustard with wire whisk until well blended. Add 1/4 cup of the dressing mixture to potatoes; toss to coat. Set remaining dressing mixture aside. Spread potatoes into lightly greased 15x10x1-inch baking pan.
BAKE 20 to 25 min. or until potatoes are tender.
COMBINE beans, peppers, onions and bacon in large bowl. Drizzle with remaining dressing mixture; mix lightly. Gently stir in warm potatoes. Serve warm.