Trim the skirt steak, removing any excess fat and cut it into 3-4 manageable pieces.

Rub kosher salt over each piece of steak and place them in a resealable bag.

In a medium bowl, whisk together olive oil, red wine vinegar, soy sauce, Worcestershire sauce, Dijon mustard, and minced garlic until emulsified. Add fresh thyme and rosemary.

Pour the marinade over the steak in the resealable bag, seal it, and refrigerate for at least 2 hours or up to 12 hours.

Remove the steak from the fridge 30 minutes before grilling and pat dry. Re-season lightly with ground pepper.

Preheat the grill to high heat (450-500°F) and cook the skirt steak for 3-4 minutes per side until achieving desired doneness (medium-rare: 125-130°F).

Let the steak rest for about 10 minutes before slicing against the grain into half-inch pieces.