In a medium sized bowl whisk together the oil, lemon zest, lemon juice, garlic, cumin, coriander, and salt. Add the chicken to the marinade and toss to coat. Marinate the chicken for 20 minutes. While the chicken is marinating, soak the skewers in water if wooden.
Thread 4 pieces of the chicken and 4 grapes onto the skewers, alternating them. Spray a grill pan with cooking spray and preheat over a medium-high heat, or prepare an outdoor grill. Grill the chicken until cooked through, about 3 to 4 minutes per side. Sprinkle with mint and serve with lemon wedges.