In a large saucepan, cook beans and corn, covered, in lightly salted boiling water for 5 minutes. Drain and rinse with cold water. Cut corn from cobs. For slaw, in large bowl combine beans, corn, radishes, carrot, and sweet pepper. For dressing, in a screw-top jar combine oil, lemon juice, sugar, tarragon, mustard, and 1/8 tsp. each salt and pepper. Cover and shake. Drizzle dressing on vegetables; toss to combine. Set aside to marinate while grilling hot dogs (or refrigerate up to 6 hours).
Preheat grill to medium. Grill hot dogs, covered 6 minutes, turning until grill marks form. Serve in buns topped with slaw. Makes 8 servings.