Warm Potato Salad
["1 1/2 lb. small red skinned potatoes with skins, quartered", "1/2 lb. green beans, trimmed and cut into 1 1/2-inch pieces", "1 onion, chopped", "2 Tbsp. oil", "1/4 c. Dijon mustard", "3 Tbsp. white vinegar", "1/2 tsp. salt", "1 Tbsp. sugar", "1/8 tsp. pepper"]
["Cook potatoes in lightly salted boiling water for 15 minutes or until tender.", "Add the green beans for the last 5 minutes of cooking."]
["red skinned potatoes", "green beans", "onion", "oil", "Dijon mustard", "white vinegar", "salt", "sugar", "pepper"]