Preheat indoor or outdoor grill to MEDIUM-HIGH. Cut 1-inch-long slits about 1/2-inch deep and about 1-inch apart over the top and bottom of the roast then place it in a rimmed dish. In a small bowl, combine soy sauce, chopped cilantro, liquid smoke (if using), oregano, garlic and pepper; spoon mixture into the slits in the roast and pour the remainder over the meat. Grill roast until desired level of doneness is achieved, turning once. Transfer meat to a cutting board and allow it to rest for 5 minutes to redistribute its juices; thinly slice across the grain (diagonally) and enjoy!