Whisk together the marinade ingredients in a mixing bowl or directly in a Ziploc bag. Add the chicken thighs, ensuring each piece is evenly coated. Seal the bag and refrigerate for at least 3 hours, but overnight is even better. The yogurt and aromatics will work magic while you wait.
While the chicken marinates, make the tzatziki. Slice the cucumbers lengthwise and scoop out the seeds with a spoon. Grate the cucumber, then wrap it in a paper towel or clean kitchen cloth and squeeze out excess water. Combine the grated cucumber with yogurt, lemon juice, olive oil, garlic, salt, and pepper. Give it a good mix and pop it in the fridge to chill and meld those flavors.
Dice the cucumbers, tomatoes, and onions. Toss them together in a bowl with a pinch of salt, pepper, and parsley if you're using it. Keep it simple yet vibrant!
Heat your grill pan or outdoor grill over medium-high heat. Lightly oil the surface to prevent sticking. Cook the marinated chicken thighs for about 3–4 minutes on each side, until they’re beautifully charred and cooked through. Chicken should hit an internal temperature of 165°F (75°C). Allow it to rest for 5 minutes before slicing into bite-sized pieces.
Take a warm pita and lay a generous strip of tzatziki down the center. Add a handful of salad, juicy chicken, and any extras like roasted peppers or crumbled feta. Fold the pita into a wrap, secure it parchment if needed, and get ready to dig in.