Preparation - To prepare the marinade - Place 1 tablespoon olive oil, 1 tablespoon wine vinegar, and 1/4 tsp. each of the salt, pepper and dry mustard in a food processor or blender. Process for 15 seconds. Add 2 more tablespoons olive oil and process for 10 seconds. Add the remaining wine vinegar, the remaining 3 tablespoons olive oil, plus the lemon juice, garlic and chives. Process for about 15 more seconds. Pour the marinade mixture into a bowl. Place the chicken pieces in the marinade and refrigerate for at least 4 hours or overnight. Prepare a gas grill or charcoal grill. Spray the grill rack with non-stick cooking spray. Remove the chicken from the marinade and place the chicken pieces on the prepared grill, skin side up, about 8" above medium hot coals. Sprinkle with the remaining 3/4 tsp. salt and 1/4 tsp. pepper. Grill for about 30 minutes, turning and basting with the marinade every 10 minutes. Discard the remaining marinade. Grill for about 15 to 20 more minutes or until the chicken is tender and juices run clear.