Prep the marinade. In a small bowl whisk together the lime juice, Cajun seasoning, cinnamon, cacao powder, chipotle chili pepper, onion powder, salt, pepper and olive oil. Pour over the bison flank steaks in a shallow pan or in a baggie. Marinate at room temperature for one hour.
Preheat outdoor grill to 450 F. Drizzle one tablespoon of olive oil to coat the bottom of a large cast iron skillet. Arrange the sliced peppers, onions and jalapeno. Pour the lime juice over the tops of the vegetables. Season with the garlic powder, onion powder, salt and pepper. Drizzle the remaining olive oil across the veggies.
In a smaller skillet add about one cup of cooked Spanish rice, one cup drained black beans and one cup refried beans. Season with salt and pepper. Sprinkle cotija cheese generously over the top.
For the chipotle ranch sauce, in a small bowl combine the ranch dressing, chipotle adobo sauce and lime juice. Stir until smooth then chill while you grill.
Place both cast iron skillets onto the grill. Cook for about 15 minutes. Keep on the grill during the next step.
Next, add the marinated bison flank steaks to the grill. Grill 3 minutes per side for rare, 4 minutes per side for medium rare and 5 minutes per side for medium rare to well-done. The internal temperature should read at least 125 F. Let the steaks rest 10 minutes. Continue to cook the cast iron components on the grill while the steak rests.
Remove the cast iron components from the grill and let cool for 5-10 minutes. Slice the flank steak across the grain.
Serve the cooked steak, fajita veggies and baked rice and beans along with tortillas, shredded lettuce, diced tomatoes, sour cream, chopped avocado, cotija cheese, salsa and all of your favorite fajita toppings. Assemble to taste and enjoy!