In a large bowl, mix the yogurt, lemon juice, olive oil, crushed garlic, and all the spices. Stir well.
Add the thinly sliced chicken and make sure it's completely coated with the marinade. Cover the bowl and refrigerate for at least 2 hours, ideally overnight.
Heat a large skillet over medium-high heat with a little oil. Add the marinated meat and cook until it's golden brown and cooked through (about 5-7 minutes).
If you prefer, you can spread the meat on a baking sheet and bake it in an oven at 200°C (400°F) for about 15 minutes, or until it's crispy on the edges.
Take the pita bread and warm it slightly. Place the cooked meat in the center, along with slices of onion, tomatoes, and pickles. Add a generous amount of your favorite sauce (tahini or garlic sauce).
Roll it up tightly and serve immediately, ideally with french fries or a fresh salad.