Cut the zucchini and yellow squash lengthwise into ¼-inch slices. Arrange the slices on a platter or in a baking dish and sprinkle both sides with the garlic, oregano, mint, hot pepper flakes, and lots of salt and pepper. Drizzle 2 tablespoons oil over them, turning the slices several times to coat both sides. Let marinate for 15 minutes.
