Heat Potatoes, hot water, onion and salt to boiling in 2 quart saucepan; reduce heat. Cover and simmer 5 minutes; drain. Rinse with cold water until potatoes are cool; drain thoroughly.
Stir together mayonnaise and mustard in large bowl. Add potatoes and remaining ingredients; toss until coated. Cover and refrigerate at least 1 hour until chilled.
Makes 5 servings, about 3/4 cup each
1 Serving: 310 calories (180 calories from fat); 20 g fat (4 g saturated); 100 mg cholesterol; 980 mg sodium; 29 g carbohydrate (3 g dietary fiber); 6 g protein.