Prepare garlic sauce by whisking together Greek yogurt, minced garlic, lemon juice, tahini, and salt until smooth and creamy. Refrigerate while preparing chicken.

Cut chicken thighs into thin strips approximately 1/2 inch wide for even cooking.

In a large bowl, combine chicken strips with olive oil, paprika, cumin, garlic powder, cinnamon, salt, and black pepper. Mix thoroughly until evenly coated.

Heat large skillet over medium-high heat until very hot. Add seasoned chicken in single layer without overcrowding.

Cook chicken undisturbed for 3-4 minutes until golden-brown crust forms. Flip and cook another 3-4 minutes until fully cooked and slightly crispy.

Warm flatbreads in dry skillet for 10-15 seconds per side or briefly over open flame.

Chop kale into bite-sized pieces and slice purple onion into thin rings.

To assemble, spread generous amount of garlic sauce down center of each flatbread, leaving 2 inches on sides.

Add portion of chicken, kale, and onion rings on top of sauce.

Fold bottom edge up over filling, fold in both sides, then roll tightly from bottom to top.

Wrap bottom half of each shawarma in aluminum foil and serve immediately while hot.