1. Process garlic and 1 tsp. salt in a food processor 2 seconds or until smooth, stopping to scrape down sides as needed. Remove and reserve 1 Tbsp. garlic mixture. Stir together remaining garlic mixture, yogurt, and lime rind.
2. If applicable, remove giblets from chicken, and reserve for another use. Rinse chicken, and pat dry. Loosen and lift skin from chicken with fingers (do not detach skin); spread reserved 1 Tbsp. garlic mixture evenly underneath the skin. Place cilantro sprigs underneath skin. Carefully replace skin, and secure with wooden picks. Spread yogurt mixture evenly over chicken and inside cavity. Cover and chill 8 hours.
3. Preheat oven to 375°. Wipe excess yogurt mixture from outside of chicken with a paper towel. Place chicken on a lightly greased wire rack in an aluminum foil-lined broiler or jelly-roll pan. Coat chicken with cooking spray, and sprinkle with pepper and remaining 1/2 tsp. salt.
4. Bake at 375° for 45 minutes; cover loosely, and bake 25 more minutes or until a meat thermometer inserted into thickest portion registers 165°. Let chicken stand 10 minutes before slicing. Garnish, if desired.