Whisk ¼ cup finely chopped fresh basil leaves, 3 tablespoons white wine vinegar, 2 tablespoons finely chopped fresh chives, 1 tablespoon Dijon mustard, 2 minced garlic cloves, 1 teaspoon honey, and ¼ teaspoon kosher salt together in a large bowl. While whisking constantly, slowly pour in ¼ cup neutral oil and whisk until combined. (If you’d like a smoother vinaigrette, blend everything together with a stick or regular blender.)
Trim the ends from 2 medium zucchini. Using a vegetable peeler or a mandoline, thinly slice the zucchini lengthwise into wide ribbons.
Add the zucchini, 2 heaping cups halved cherry tomatoes, ¼ cup pitted Kalamata olives, and ¼ cup pitted Casaveltrano olives if using. Toss until everything is evenly coated.
Transfer to a serving platter. Garnish with 2 ounces crumbled feta cheese and freshly ground black pepper if desired.
