01 - In a large mixing bowl, combine the yogurt, lemon juice, vegetable oil, minced garlic, grated ginger, ground cumin, ground coriander, smoked paprika, turmeric, garam masala, cayenne pepper, sea salt, and black pepper. Whisk until the mixture is smooth and uniform in color.
02 - Add the cubed chicken thighs to the marinade, tossing thoroughly to ensure every piece is evenly coated. Cover the bowl with plastic wrap and refrigerate for at least 4 hours, or preferably overnight for maximum flavor penetration.
03 - If using wooden skewers, submerge them in water and soak for at least 30 minutes to prevent burning during grilling. Metal skewers require no preparation.
04 - Remove the chicken from the refrigerator. Thread the marinated chicken cubes onto the skewers, leaving a small gap between each piece to allow even heat circulation and thorough cooking.
05 - Preheat an outdoor grill or oven broiler to high heat. Place the skewers on the grill and cook for 15 to 20 minutes, turning occasionally with tongs, until the chicken is cooked through with slightly charred edges. The internal temperature of the thickest piece should reach 165°F.
06 - Remove the skewers from the grill and let them rest for 3 minutes to allow the juices to redistribute. Serve hot, garnished with thinly sliced red onion, lemon wedges, and fresh cilantro leaves. Accompany with green chutney or raita on the side if desired.