1Prepare the chicken: In a bowl, mix olive oil, tomato paste, lemon juice, garlic powder, onion powder, cumin powder, red chili powder, turmeric powder, salt, and black pepper. Add chicken strips and marinate for at least 30 minutes.
2Cook the marinated chicken in a pan with olive oil until cooked through.
3Prepare the garlic mayonnaise: Mix mayonnaise, garlic, parsley, salt, and lemon juice in a bowl.
4Prepare the sumac onions: Mix sliced onions, parsley, lemon juice, and sumac in a bowl.
5Assemble the shawarma: Warm pita bread in a pan, then fill with chicken, cucumbers, tomatoes, pickled cucumbers, harissa sauce, garlic mayonnaise, and French fries.