Combine the cilantro, soy sauce, brown sugar, canola oil, water, sesame oil, minced garlic, jalapeño, black pepper, and coriander in a large zip lock bag. Mix until well combined. Add the flanken short ribs and marinate for 8-24 hours.
Place the rack near the top of the oven. Heat the oven to high broil (should be about 550 degrees).
Line a baking sheet with tin foil. Place two wire racks on sheet pans then lay ribs in a single layer on top of the racks.
Place into the oven and broil, with the door cracked, for 4-5 minutes on each side, making sure to watch the ribs very carefully so they won't burn and be ruined.
Remove from the oven and place on a serving platter. Sprinkle the short ribs with toasted sesame seeds and chopped green onions before serving. Enjoy.