In a large mixing bowl, whisk together the yogurt, lemon juice, olive oil, garlic, tomato paste, paprika, cumin, cinnamon, oregano, salt, and pepper until smooth.

Add the cubed chicken to the marinade and toss until every piece is thoroughly coated.

Cover the bowl with plastic wrap and refrigerate for at least 4 hours, though overnight is recommended for optimal tenderization.

If using wooden skewers, soak them in water for 30 minutes prior to grilling; otherwise, use metal skewers.

Thread the marinated chicken pieces onto the skewers, leaving a small amount of space between each piece to ensure even cooking.

Preheat an outdoor grill or indoor grill pan to medium-high heat.

Place the skewers on the grill and cook for 12 to 15 minutes, rotating every 3 to 4 minutes, until the internal temperature reaches 165°F (74°C) and the edges are slightly charred.

Remove from heat and allow the chicken to rest for 5 minutes before serving with pita bread and garlic sauce (toum).