Use a fork to poke holes in the skirt steak, covering both sides.
Place lime juice, brown sugar, cilantro, 2 tablespoons of olive oil, chili powder, garlic, cumin, and salt in bowl.
Mix ingredients in bowl.
Place the skirt steak in a large zip bag.
Pour the marinade over the steak.
Zip the bag and shake to coat the steak on all sides.
Let steak rest at room temperature for at least 1 hour and no longer than 8 hours.
Preheat an outdoor grill to 375 degrees.
Grill steaks for 7 to 10 minutes per side, turning once for medium-rare.
Remove steaks and allow to rest for 5 minutes.