- Working in 3 batches, cut potatoes into 3/4-inch cubes and steam until tender, about 10 minutes. Set aside.
- Meanwhile, whisk oil, vinegar, salt and pepper in large bowl to blend. Add hot potatoes and gently toss until most of dressing is absorbed.
- Stir mayonnaise, pickle juice and mustard in another large bowl to blend. Add all remaining ingredients and reserved potato mixture; toss to coat. Season to taste with salt and pepper. Cover and refrigerate.
- DO-AHEAD TIP: Salad can be prepared 1 day ahead. Keep refrigerated.