Sicilian Potato Salad (Insalata Vastasa)

Name: Sicilian Potato Salad (Insalata Vastasa)
Prep time: 15 min
Cook time: 15 min
Total time: 30 min
Cuisine: European, Italian, Mediterranean
Ingredients: 1/3 cup extra virgin olive oil; 1 teaspoon lemon zest, from 1 lemon; 1/4 cup freshly squeezed lemon juice, from 1 lemon; 1 teaspoon dried oregano, such as Filippone; 1 teaspoon kosher salt, divided, plus more for the water; 1/2 small red onion, thinly sliced; 1 pound baby Yukon gold potatoes; 1/2 pound green beans, trimmed and cut into 1 inch pieces; 1 cup cherry or grape tomatoes, halved; 1/2 cup pitted green olives, such as Castelvetrano or Cerignola; 1/2 cup pitted black olives