In a large bowl, combine all the ingredients for the marinade and mix until well blended.
Add the chicken thigh fillets and mix to coat completely. Cover bowl with plastic wrap and marinate for at least 1 hour or place in the fridge overnight.
Make the yogurt-garlic sauce by simply mixing all the ingredients in a bowl. You can divide the sauce and add some sriracha to one part so you have two options. Cover and refrigerate until ready to use. You can also transfer sauce in a squeeze bottle for ease of use.
Grill the chicken thighs using a griddle pan or over charcoal. Grill the first side for 4 to 5 minutes until nicely charred, then turn and grill for another for 3 to 4 minutes or until charring is even.
For oven grilling: Preheat the oven to 425°F. Arrange the marinated chicken on a baking sheet pan lined with parchment paper. Roast for 30 minutes at 220°C/425°F. Move the pan to the top rack and broil very briefly until a little charred. Remove from the oven.
Transfer grilled chicken into a deep serving dish with a cover or use a plate. Let it rest for 5 minutes before slicing. Slice the chicken into strips and place them back into the dish.
Serve alongside the pita bread or tortilla wrap, sliced lettuce, tomatoes, onions and yogurt-garlic dip.
To make a wrap, lay a pita bread or tortilla on a plate lined with parchment paper or foil. Top it with chicken, lettuce, tomatoes, and onions. Drizzle some yogurt-garlic sauce on top then fold to and wrap.