Grab your meat tenderizer and pound the chicken until it's about 1/4 inch thick.
Put the garlic, apple cider vinegar, lemon juice, olive oil, greek yogurt, oregano, cumin paprika, salt, pepper, and cayenne pepper in a mixing bowl and mix well.
Add the marinade into a large plastic bag that you can seal. Put the chicken inside the bag and squish it around so that the chicken is totally covered. Once covered, place the bag of chicken in the fridge for at least 2 hours.
As the chicken is marinating in the fridge, make the homemade tzatziki sauce.
After the timeframe has passed, take the chicken out of the marinade. It's time to cook the chicken on the stovetop. Put a tablespoon of oil into a skillet and turn it to medium heat. Cook the chicken for 3-4 minutes on each side (this will sear the chicken while it cooks), then turn the chicken over and cook until it's cooked all the way through.
Once the chicken is cooked, put the pieces of chicken on a cutting board and let it rest for 5 minutes. After that time has passed, slice the chicken meat into strips.
Soften the pita bread by warming it in the microwave for a few seconds. Once it's warm, fill it with the chicken, tzatziki sauce, and garnishes.