Cover potatoes with water, bring to a boil and salt the water. Cook potatoes until just tender, about 15 minutes, then drain and return them to the hot pot.
Add vinegar, olive oil, parsley, salt, and pepper to the pot. Toss to coat and transfer to a serving dish. Refrigerate overnight or for a minimum of 2 hours. Sprinkle with 1 tablespoon of fresh chopped chives before serving.