Step 1Pat the steaks dry and place in a large zip-top bag.
Step 2Combine the garlic, oregano, vinegar, olive oil, adobo seasoning and salt in the bowl of a pilón or mortar and pestle, or a small food processor. Grind into a thin paste, then pour the marinade over the steak. Zip the bag then shake well to coat the meat, rubbing in gently as needed. Let rest on the counter for 10 to 20 minutes, or refrigerate overnight if you have time. Be sure to let the steak come to room temperature before grilling.
Step 3If using a charcoal grill, start by building a fire with hardwood and kindling, then adding lump hardwood charcoal once the fire is kicking. Allow the fire to mellow. If using a gas grill, set the temperature to 500 degrees.
Step 4Meanwhile, make the wasakaka: Combine the lime juice, parsley, cilantro, oregano, olive oil, garlic, salt and pepper in a small bowl and whisk to incorporate. If you’d like a creamier sauce, blend in a small food processor or blender. (Wasakaka will keep for 3 or 4 days in a sealed jar in the refrigerator.)
Step 5Once the grill is ready, remove skirt steak from the bag and shake off excess marinade. Place on the grill and sear for 1 to 3 minutes. Using tongs, pull up the corner to ensure the steak has a good dark char, bordering on burned in places, before flipping, then cook for 1 more minute for rare, 2 minutes for medium-rare. Be careful not to overcook or steak will be tough.
Step 6Remove steak from grill and let rest for 5 to 7 minutes. Slice into strips and pour over wasakaka, or serve sauce on the side. Taste and sprinkle with additional salt, if desired.
TIP
Skirt steak and tri-tip are very different cuts, but both work well for this recipe. Because tri-tip is typically a thicker, rounder cut than skirt steak, you’ll need to flip it a few more times on the grill.