In small bowl combine olive oil, garlic, chili flakes, oregano, rosemary and lemon zest. Whisk together marinade. Cut chicken into 3/4 inch cubes. Alternate chicken and grapes and thread onto 12 skewers. Place skewers into a baking dish or pan large enough to hold them. Pour marinade over skewers, coating each one. Marinate for 4-24 hours. Remove skewers from marinade and let excess oil drip off. Season with salt. Grill on barbecue until chicken is cooked through, about 3-5 minutes on each side. Arrange on serving platter and drizzle with additional olive oil and lemon juice.
Nutritional Stats: Calories 299; Protein 27g; Fat 15g; Calories from Fat 52%; Carbohydrate 14g; Cholesterol 66mg; Fiber 1g; Sodium 370mg.