Thinly slice the flank steak against the grain into bite-sized strips.
In a small bowl, toss the steak strips with chili powder, sea salt, black pepper, and lime juice until evenly coated.
Heat a non-stick skillet over medium-high heat with the avocado oil.
Add the sliced bell peppers and red onion to the skillet, sautéing for 3-4 minutes until they are tender-crisp.
Add the seasoned steak to the skillet and sear for 2-3 minutes until browned and cooked through, then remove the steak and veggie mixture from the pan.
Wipe the skillet clean and place the sprouted grain tortilla in the pan over medium heat.
Sprinkle half of the cheddar cheese on one side of the tortilla, top with the steak and veggie mixture, and add the remaining cheese.
Fold the tortilla in half and press down firmly with a spatula.
Cook for 2 minutes per side until the tortilla is crispy and the cheese is fully melted.
Slice into wedges and serve immediately while hot.