In a mixing bowl, whisk together olive oil, minced garlic, and lime juice. Add cumin, chili powder, and a pinch of salt and pepper.

Place skirt steak in a resealable bag and pour the marinade over it. Seal tightly and refrigerate for at least one hour, preferably overnight.

Preheat your grill to medium-high heat (around 400°F to 450°F) about 20 minutes before grilling.

Grill the marinated skirt steak for about 4 minutes on each side for medium-rare.

Let the steak rest for 5 minutes before slicing against the grain into thin strips.

Warm the tortillas on the grill for about 30 seconds on each side, then fill with sliced steak, onions, cilantro, and additional toppings.

Serve the tacos on a platter with lime wedges to garnish and enjoy immediately.