Rub taco seasoning evenly on both sides of the steak. Marinate for an hour or longer if you have the time, otherwise do it just prior to cooking.
Heat oil in a cast iron skillet and sauté the steak on both sides for about 5-8 minutes (each side) depending on your doneness preference. Once cooked remove from heat and set aside while you prepare the salsa. Meats need 5-10 minutes before cutting to lock in all the juices and flavors. Slice the steak into thin strips.
Salsa
Add all the ingredients to a small glass bowl and mix to combine.
Assembling Tacos
Heat both sides of the tortilla on a non-stick skillet. Place a layer of shredded cabbage followed by a generous serving of steak strips and top with mango jalapeño salsa. Garnish with fresh cilantro and lemon juice. Serve