In a medium bowl, whisk together ¼ cup olive oil with the juice of 2 fresh limes, along with 1 tablespoon chili powder, 1 teaspoon cumin, ½ teaspoon garlic powder, and a pinch of salt and pepper until a fragrant paste forms.

Place 1 to 1.5 pounds of flank steak in a shallow dish or zip-top bag. Pour the marinade over the steak, ensuring it's well-coated on all sides. Seal the bag or cover the dish and let it marinate for at least 30 minutes at room temperature or up to overnight in the refrigerator.

Preheat your grill or cast iron skillet over medium-high heat for about 5 minutes. Test by flicking water onto the surface; if it sizzles and evaporates immediately, it's ready.

Once hot, place the marinated flank steak on the cooking surface. Cook for about 4-5 minutes on each side for medium-rare doneness. Avoid moving the steak too much to achieve a nice crust.

Transfer the cooked steak to a cutting board and let it rest for about 5 minutes to allow juices to redistribute. Then slice against the grain into thin strips.