Large eggs, 4

Ice

Yukon Gold potatoes, 2 medium (peeled and cut into 1-inch cubes)

White wine vinegar, ½ cup

Kosher salt

Freshly ground black pepper

Extra-virgin olive oil, ½ cup (plus more for serving)

Scallions, 2 (thinly sliced on the bias)

Flat-leaf parsley leaves, ¾ cup (finely chopped)

Olive oil-packed tuna, one 6-ounce can or jar (preferably ventresca tuna belly)

Rustic Italian bread, sliced