Combine the spices for the steak (chili powder-cumin) and season the steak generously on both sides along with the salt and pepper. You may have some extra seasoning mix; reserve for another use. Let the steak sit for 20 minutes.
Meanwhile, make the blood orange salsa. Combine the blood orange and cara cara segments with the blood orange zest, red onion, cilantro, jalapeno, olive oil, and lime juice. Season with salt and pepper and let sit for 20 minutes.
Heat 1 tablespoon oil in a cast-iron pan or saute pan over medium heat. Cook the steaks until the desired degree of doneness. Remove from heat and let rest for 10 minutes. Slice the steak into thin strips.
Heat the tortillas and assemble the tacos with the blackened steak, blood orange salsa, avocado, cilantro, cotija, and limes. Serve immediately.