Cover potatoes with salted cold water; by 2 inches in a 3-quart saucepan and simmer uncovered until just tender, 15 to 25 minutes, depending on size of potatoes. Drain in a colander and cool slightly.
While potatoes are simmering, whisk together vinegar and salt in a large bowl until salt is dissolved.
When potatoes are just cool enough to handle, peel and cut into 1-inch pieces, adding to vinegar mixture as cut, and toss gently with a rubber spatula to combine. Let cool to room temperature, then add remaining ingredients and salt and pepper to taste and stir gently to combine. Serve at room temperature or chilled.
