Add all ingredients except the flank steak to a large ziplock bag or a shallow bowl. Whisk until everything is combined, and add flank steak to the bag or pan. Flip the meat around so that it gets coated in the marinade. Refrigerate for 2 - 12 hours.
2 pound Flank Steak, 2 Tablespoon Chili Powder, 1 teaspoon Cumin, 1 teaspoon Oregano, 1 teaspoon Salt, 1/4 teaspoon Cayenne Pepper, 1/4 cup Olive Oil, 1/4 cup Fresh Lime Juice