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 oven rack near the top of the oven. Heat the oven to high broil (it should be near 550 degrees).
Line a baking sheet with foil. Place a wire rack on the baking sheet, then lay ribs in a single layer on top of the rack.
Place in 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.