Wash, peel and cut the potatoes into 1⁄2 inch dice, about 2 1⁄4 cups. Place in a pot with 5 cups of water and 1 teaspoon salt.
Bring to a boil and cook until the potatoes are tender when inserted with a fork, about 10 to 12 minutes.
In a small bowl mix Yogurt (Dairy or Vegan), vinegar, salt and pepper, add the oil and mix again.
Drain the potatoes, discard the water and put them back into the pot or in a bowl. Add the vinegar mixture, sprinkle the cilantro, mix gently and serve.