To Marinate the Flank Steaks:
In a small bowl mix all dry ingredients together. Mix in the lime zest and lime juice. Drizzle in the vegetable oil and stir to make a marinade. Place each flank steak in a separate plastic bag and divide the marinade between them. Seal the bags and work the marinade into the flank steaks until they are evenly coated. Let sit for 30 minutes.
To Prepare the Flank Steaks:
Over the sear burner set to high grill the flank steaks 5 minutes per side turning once or until desired internal doneness is reached. Try making fajitas by severing the flank steak with tortillas and grilled vegetables.