Combine 1 teaspoon lemon rind, 2 tablespoons lemon juice, 1 teaspoon olive oil, 1/4 teaspoon black pepper, and 2 garlic cloves in a large zip-top plastic bag. Add pork; seal bag, and marinate in refrigerator 2 hours, turning bag occasionally.
. Prepare grill.
. Remove pork from bag; discard marinade. Thread pork, bell pepper, and onion alternately onto each of 4 (12-inch) skewers. Sprinkle with salt.
. Place skewers on grill rack coated with cooking spray. Cover and grill 13 minutes or until pork is slightly pink, turning occasionally. Remove from grill; keep warm.
. Combine remaining 1/2 teaspoon lemon rind, remaining 1 tablespoon lemon juice, remaining 2 teaspoons olive oil, remaining 1/4 teaspoon pepper, remaining 1 garlic clove, chicken broth, parsley, and olives; stir well with a whisk. Serve sauce over kebabs.