Prep the marinade: In a large bowl, whisk the olive oil, yogurt, garlic, lemon juice, zest, cumin, coriander, paprika, turmeric, cinnamon, cayenne, salt, pepper, and vinegar until smooth.
Marinate the chicken: Pat the chicken dry and add it to the bowl.
Toss to coat every piece. Cover and chill for at least 30 minutes, or up to 24 hours for deeper flavor.
Option 1 - Oven roast: Heat the oven to 425°F (220°C). Spread the chicken on a parchment-lined sheet pan with the sliced red onion.
Roast 20–25 minutes, flipping once, until cooked through. For extra char, broil for 2–3 minutes at the end.
Option 2 - Stovetop: Heat a large skillet over medium-high. Add a little oil and cook the chicken in batches 4–5 minutes per side until browned and cooked through.
Add the onions to the last batch to soften and char slightly.
Option 3 - Grill: Heat the grill to medium-high and oil the grates. Grill the chicken 4–6 minutes per side, depending on thickness, until nicely charred and cooked through.
Rest and slice: Transfer cooked chicken to a cutting board. Let rest for 5 minutes, then slice thinly across the grain.
Toss the slices with any pan juices for extra moisture.
Make a quick sauce (optional): Stir tahini with a little lemon juice, garlic, salt, and water until creamy. Or mix yogurt with garlic, lemon, olive oil, and salt.
Assemble: Serve in warm pita with sauce, tomatoes, cucumbers, and herbs, or over rice with a side salad and pickles. Finish with a squeeze of lemon.