In a large bowl, combine the Greek yogurt, olive oil, minced garlic, za’atar, oregano, lemon juice and zest, salt and pepper.
Stir in the chicken or pork cubes to completely coat, cover and let it all marinate for at least 1-2 hours in the refrigerator.
Soak wooden skewers for 30 minutes in water and then thread 4-5 pieces of meat on to each one with pieces of red onion and lemon in between. (Twist the lemon slices in half before threading it on. If you have never tried eating thinly sliced, grilled lemon, give it a try. I love it, it almost caramelizes!)
Place the skewers on the grill, rotating frequently until the meat is cooked through, (internal temperature of the chicken chunks should reach 165 degrees for safety, pork we cook more to 150.)
Serve skewer meat over rice, with flat bread or even in tortillas or lettuce cups.