Add the chipotle peppers, mango, oil, lime, garlic, salt, & cumin to a blender. Blend on high speed until smooth. Set about ½ cup of the marinade aside.
Place the steak in a container with a lid, then cover with the remaining marinade. Use clean hands to cover the steak. Place in the refrigerator to marinate for at least 20 minutes, or overnight to prep ahead of time.
Assemble the corn salad by combining all ingredients in a mixing bowl. Place in the refrigerator, covered.
Heat a skillet or grill pan over medium-high heat, then add the marinated steak without overlapping. Cook for 3-4 mins per side without moving (until 130 to 135 degrees for medium rare). Set aside on a cutting board to rest for at least 10 mins, then slice.
Warm/heat the tortillas. Assemble the tacos with a few spoonfuls of corn salad and several small pieces of the steak. Alternatively, prepare as rice bowls. Top with reserved marinade and sprinkle chopped cilantro.