Prepare the Chimichurri:
In a mixing bowl, mash the avocado until smooth. Add parsley, cilantro, garlic, red wine vinegar, olive oil, lime juice, salt, and pepper. Mix until well combined. For a smoother sauce, blend the ingredients in a food processor. Adjust seasoning to taste and set aside.
Season the Steak:
Pat the skirt steak dry with a paper towel. Rub both sides with olive oil, salt, pepper, and garlic powder. Let it sit at room temperature for 15–20 minutes.
Cook the Steak:
Heat a cast iron skillet or grill over high heat until smoking hot. Add the steak and cook for 3–4 minutes per side for medium-rare, or longer if you prefer. Avoid overcooking as skirt steak can become tough.
Rest the Steak:
Remove the steak from the heat and let it rest for 5–10 minutes to allow the juices to redistribute.
Slice and Serve:
Slice the steak against the grain into thin strips. Top with a generous amount of avocado chimichurri and serve immediately.