While the cilantro is bundled, chop the end with the stems about 2 inches up. Add the cilantro to a food processor.
Remove the seeds and stem from the jalapeno. Add to the food processor along with the cilantro.
Remove the skin from the garlic cloves, halve and add to the food processor.
Add the remaining ingredients for the marinade in the food processor and process on high speed for about 30 seconds or until all large chunks disappear.
Put the steak in a resealable gallon sized bag. Cover it completely with the marinade, reserving ⅓ of the marinade in the basin of the food processor to be used when serving. Seal the bag and store the marinating steak in the fridge along with the reserved marinade. Marinate the steak for at least 2 hours, but up to overnight.
Preheat your grill to high heat. If using a grill pan or skillet, you will want to heat it to medium-high heat and allow it to properly heat up before cooking so that you can get a proper sear without burning or undercooking.
Lightly brush the grill or grill pan with oil. This is not necessary, however it can help prevent the meat from sticking.
Remove the steak from the marinade. Pat dry with a paper towel and discard any leftover marinade.
Once the grill is preheated, add the steak. Cook for 6-8 minutes per side depending on your desired level of doneness. You can use a meat thermometer for the most accurate way to get desired level of doneness. These cuts of meat are all fairly lean and will taste best cooked with a decent amount of pink still in it.
Once the meat has cooked, remove from the grill and let rest for 10 minutes before slicing. Once rested, slice the steak against the grain in to thin slices.