In a small food processor, combine parsley, cilantro, olive oil, vinegar, garlic, oregano paste, dried chili peppers and 1⁄2 tsp salt and process into a smooth paste.
Preheat barbecue to high. Place beef in a shallow baking dish and spoon half the paste overtop, spreading over both sides of meat with back of spoon.
Sprinkle both sides of beef with remaining salt. Grill approx. 7 min. per side for medium-rare. Do not flip more than once. Remove beef from barbecue and let rest, 10 min. Thinly slice against the grain and serve with remaining paste.