Prep the chicken: Slice the chicken into thin strips or small pieces. This helps it cook quickly and evenly.
Mix the quick marinade: In a bowl, combine olive oil, lemon juice, zest (if using), garlic, oregano, cumin, smoked paprika, salt, and pepper.
Coat the chicken: Add the chicken to the marinade and toss well.
Let it rest for 10–15 minutes while you prep the toppings. If you have more time, 30 minutes is great, but not essential.
Prep the veggies: Halve the tomatoes, dice the cucumber, slice the onion, and chop the herbs. Crumble the feta.
Heat the pan: Set a large skillet or grill pan over medium-high heat.
Add a light drizzle of oil if your pan isn’t nonstick.
Cook the chicken: Add the chicken in a single layer. Don’t crowd the pan. Cook 3–4 minutes per side until browned and cooked through.
Work in batches if needed.
Warm the pita: While the chicken cooks, warm the pitas in a dry skillet for 30–60 seconds per side, or wrap them in foil and heat in a 300°F (150°C) oven for a few minutes.
Rest and slice (if needed): Let the chicken rest for 2 minutes, then slice any larger pieces. Squeeze a little lemon over the top for brightness.
Assemble: Spread tzatziki on each pita. Add chicken, tomatoes, cucumber, onion, and feta.
Top with dill or parsley. Add greens, olives, or pickled onions if you like.
Finish and serve: Fold the pita and serve with extra tzatziki and lemon wedges. Add a pinch of red pepper flakes for heat.