Grilled Coriander-Cumin Chicken with Cilantro-Yogurt Dipping Sauce

To make chicken: Place all ingredients (except chicken) in a blender. Puree until smooth. Place chicken pieces in a mixing bowl, add spice mixture and, using your hands, toss chicken to coat. Cover with plastic wrap and marinate at room temperature for 1 hour, or refrigerate up to 8 hours. To make dipping sauce: Meanwhile, in a small serving bowl, combine yogurt, cilantro and lime juice; mix well. Stir in salt and pepper. Adjust seasoning to taste. Cover and refrigerate until ready to serve. Preheat gas grill to medium, or prepare a charcoal grill for direct grilling over medium heat. Place chicken pieces on the grill, the breasts skin side down. Cover and cook, turning occasionally, 20 to 25 minutes. Chicken should be browned, crusty and cooked through, so juices run clear when pierced with a fork. Remove cooked pieces to a serving platter; keep warm in a low oven until the rest of the chicken is done. Garnish with cilantro sprigs. Serve with dipping sauce on the side.