About ten years ago, I came across a recipe for a grilled potato salad in an issue of Cooks Illustrated. I was intrigued by the grilling technique, and it was the first time I'd made a potato salad with vinaigrette instead of mayonnaise, which was a revelation. The other thing I loved about the recipe was this clever technique: the just-grilled potatoes are tossed first with a little rice vinegar, which absorbs quickly into the warm potatoes, and then with a couple of handfuls of arugula, which wilts gently under their heat.

Potato Salad With Arugula & Dijon Vinaigrette

Ingredients 

• 1/2 small red onion, peeled and roughly chopped
• 2 pounds new potatoes, scrubbed and cut into bite-sized pieces
• Salt
• 1 tablespoon rice vinegar
• Freshly ground black pepper
• 2 tablespoons finely chopped chives
• 3 cups arugula, stems removed, washed and dried and very roughly chopped
• 2 tablespoons red wine vinegar
• 1 tablespoon Dijon mustard
• 5 tablespoons good olive oil

• Directions

  1. Put the onion in a small bowl and cover with cold water (this will remove some of the bite). Put the potatoes in a large pot of generously salted water. Bring to a boil over high heat.
  2. Lower the heat so the water is barely simmering and cook for about 10 minutes, until you can pierce the potatoes with the tip of a sharp knife and it slips out easily. Drain the potatoes well and pour them into a large bowl.
  3. Gently toss the warm potatoes with the rice vinegar, 1/4 teaspoon salt, and 1/2 teaspoon pepper. Add the chives, arugula and red onion and stir through.
  4. Whisk together the red wine vinegar, mustard and olive oil in a small bowl. Add salt and pepper to taste. Pour over the potato mixture and toss to combine. Serve warm or keep covered at room temperature for up to an hour.

https://food52.com/recipes/12198-potato-salad-with-arugula-dijon-vinaigrette