In a medium saucepan cook potatoes in a small amount of lightly salted boiling water for 10 to 15 minutes or until tender. Drain. Rinse with cold water. Drain.
In a mixing bowl gently toss together greens, cucumber, and radishes. Add potatoes. Gently toss. Arrange on 4 plates. Roll up the roast beef slices and arrange on top of greens mixture. Place a few tomato wedges to the side of each salad.
In a small mixing bowl stir together salad dressing and dill. Drizzle over salads. Makes 4 servings.