Antipasti Potato Salad

Name: Antipasti Potato Salad
Ingredients: 1/2 small red onion, diced; 2 pounds red-skinned potatoes, cut into 1-inch chunks; Kosher salt; 1/4 cup plus 3 tablespoons extra-virgin olive oil; 3 tablespoons red wine vinegar; 1 teaspoon sugar; Freshly ground pepper; 1 cup giardiniera (Italian pickled vegetables), drained and chopped; 1 cup diced provolone cheese (about 4 ounces); 1/2 cup chopped sliced salami (about 2 ounces); 1/2 cup marinated artichoke hearts, drained and chopped; 1/2 cup sliced green olives with pimientos; 1/2 cup fresh basil, torn