Provençal Potato Salad with Tuna Dressing

Name: Provençal Potato Salad with Tuna Dressing
Ingredients: 3 Yukon Gold potatoes (about 1 1/4 pounds), peeled and quartered; 2 zucchini (about 8 ounces), halved lengthwise and slice 1/2-nch thick; one (5-ounce) can tuna in oil; 2 tablespoons Greek yogurt or sour cream; 1 tablespoon capers; 1 small garlic clove; 1 tablespoon red wine vinegar; 2 tablespoons olive oil; Kosher salt and freshly ground black pepper; 1/4 medium red onion, chopped; 2 plum tomatoes, cut into 1-inch chunks; 1/2 cup olives (I used Niçoise), chopped; 1/4 cup torn basil leaves