Step 1Shortly before you want to eat the potatoes, peel and cut them crosswise into ¼-inch-thick rounds or ovals (oval works best for fingerling potatoes).
Step 2Bring a large sauté pan filled with 1 to 2 inches water to a boil. Stir in a generous 1 tablespoon kosher salt and add the potatoes. Cover the pan, bring back to a boil, then reduce the heat to keep the liquid at a brisk simmer. Cook the potatoes until tender, about 10 minutes.
Step 3Remove the potatoes using a skimmer or slotted spoon, giving them a little shake to remove excess water, and place in shallow bowl or rimmed platter. Douse with olio nuovo, season with finishing salt as desired and scatter parsley over all. Pass vinegar, pepper and additional oil at the table as you like.