Combine cilantro, lime juice, oil, garlic, green onions, jalapenos and cumin in a food processor or blender; pulse until smooth. Place the steak in a resealable plastic bag and pour in the coriander mixture. Place in the refrigerator to marinate for at least 4 hours or up to 24 hours.
Remove the steak from the marinade and shake off the excess marinade; discard remaining marinade. Sprinkle the salt all over the steak.Turn the grill on.
Select the red meat program and press OK. Lightly grease the cooking plates with cooking spray. Once the purple indicator light has stopped flashing, place the steak on the grill and close the lid.Cook until the indicator light has changed to the color of desired doneness; yellow for rare, orange for medium or red for well done. Transfer the steak to a cutting board and tent with foil. Rest for 5 minutes before slicing very thin.
Serve the steak with a large tossed salad and baked potatoes. The sliced steak can be used as a filling for fajitas along with grilled peppers and onions, sour cream, salsa and guacamole. For tender flank steak, it is recommended not to cook the meat past medium doneness.