Greek Potato Salad

Bring 1 to 2 inches of water to a boil in a large saucepan (or pot) fitted with a steamer basket. Add potatoes, cover and cook until tender, 12 to 15 minutes. Spread in a single layer on a rimmed baking sheet and sprinkle with 1/4 teaspoon salt; let cool 15 minutes.

Meanwhile, whisk oil, vinegar, shallot, mustard, pepper and the remaining 1/2 teaspoon salt in a large bowl. Add the potatoes, tomatoes, feta, olives and oregano; stir well to coat. Serve at room temperature or refrigerate until cold.