Heat the grill on high for at least 10 minutes (or cook in a hot skillet).
In a medium/large bowl, add the turkey, zucchini, feta, oregano, salt, pepper, and garlic. Use your hands to thoroughly mix. Form into 4 (about ½-inch thick) large patties.
Grilling instructions: lightly grease both sides of the patties. Place on the hot grill and cook, covered, for 3-5 minutes or until you have nice grill marks. Carefully flip and cook for 2-3 minutes or until cooked through.
Skillet instructions: in a large skillet, warm about 2 tablespoons oil. Add the patties, press down gently, and cook for 3-5 minutes or until it’s deeply golden brown. Carefully flip with a spatula (it can stick depending on the kind of skillet you’re using so do your best!). Cook for 3 more minutes or until cooked through. Transfer to a plate.
In the same large skillet (if using) over medium heat, warm the oil. Add the zucchini and salt and cook for about 5 minutes, stirring occasionally (scraping up any bits stuck to the pan), or until the zucchini has become soft and jammy and all of the liquid has been cooked out. Stir in the vinegar and let that cook for a minute or until the vinegar has evaporated.
In a small bowl, add the yogurt, parsley, feta, pepper, and salt. Use a fork to mix it together, mashing up the feta chunks into the yogurt.
To assemble as burgers: toast your buns on the grill or in a skillet. Place the lettuce/greens on the bottom, followed by a slice of tomato, turkey patty, sauce, zucchini, bun.
To assemble as a bowl: add your seasoned grains and/or greens to a bowl. Top with turkey patties, cucumber, tomato, and zucchini. Thin out the sauce with a squeeze of lemon and/or water and drizzle it on top.