In a blender, combine chipotle pepper, garlic, orange juice, lime juice, oil, soy sauce, cilantro, honey and chili powder to make marinade. Place steak in a plastic seal bag and pour in marinade; massage to coat evenly. Refrigerate for at least 3 hours and not more than 8 hours.
Preheat a charcoal or gas grill to medium-high. Remove the steak from the marinade, season with salt and grill for about 4 minutes a side. Transfer to a cutting board and rest for 5 to 10 minutes. Once meat has rested, slice steak across the grain diagonally.
Combine all ingredients in a bowl and stir. Refrigerate until ready to serve.
Warm the tortillas for about 30 seconds on each side in a dry skillet or on the grill, until toasty and pliable.
Serve steak strips on the warmed tortillas with avocado, cheese then topping with mango salsa.