1 pound zucchini (or any summer squash), sliced into 1/2-inch rounds
3 tablespoons olive oil, divided
3 small cloves garlic
10 mint leaves
5 basil leaves
1 heaping tablespoon capers, rinsed
2 tablespoons walnuts or pine nuts, lightly toasted
1 teaspoon red wine vinegar, more to taste
1 pinch Sea sal