Place peppercorns and coriander seeds in a large skillet over medium-high heat; cook 1 minute or until toasted. Place peppercorns and coriander seeds in a spice or coffee grinder; process until finely ground.
Combine the pepper mixture, cilantro (if desired), and next 4 ingredients (cilantro through garlic). Loosen skin from chicken breasts and thighs by inserting fingers, gently pushing between skin and meat. Rub the seasoning mixture under loosened chicken skin. Seal and marinate in refrigerator 3 to 8 hours. Remove chicken from bag; discard marinade. Place chicken on grill rack coated with cooking spray; grill 8 minutes on each side or until chicken is done. Discard skin.
Wine Note: Lots of coriander, soy sauce, and garlic, plus the char from grilling, mean this chicken will need a boldly fruity, densely textured wine partner. A great bet: Dry Creek Vineyard Old Vines Zinfandel 1998 (Sonoma County, California; $19).