Whisk the lime juice, oil, sugar, smoked paprika, garlic powder, chili powder and salt in a small bowl until the sugar is completely dissolved.

Add the marinade and the steak to a 1-gallon zip-top bag or baking dish. Toss the steak to coat, then press as much air out of the bag (if using) as possible, or cover with plastic wrap (if using a baking dish). Refrigerate for 2-4 hours, or overnight.

Preheat a grill or grill pan to high heat. Remove the steak from the marinade, shaking off any excess. Set the remaining marinade aside.

Grill the steak for 3 minutes per side, or until the internal temperature registers 145°F (for medium rare). Remove from the grill, tent with foil, and allow to rest for 10 minutes while you prepare the fajita veggies.

Preheat a large cast iron skillet to high heat. Remove the steak from the marinade, shaking off all excess. Set the remaining marinade aside.

Add 2 teaspoons neutral-flavored oil to the pan. Cook the steak for 3 minutes per side, or until the internal temperature registers 145°F (for medium rare). Remove from the pan, tent with foil, and allow to rest for 10 minutes while you prepare the fajita veggies.

Heat a cast iron skillet to medium high heat – use the same skillet you cooked the steak if using the stovetop option. Add 2 teaspoons of oil, along with the veggies. Cook for 5-10 minutes, or until the vegetables are softened and begin to char, stirring frequently.

While the veggies cook, thinly slice the steak against the grain.

Add the reserved marinade to the veggies and bring to a strong simmer. Add the sliced steak and stir to combine.

Serve immediately with toppings of your choice.