Slice the flank steak into thin strips against the grain.
In a small bowl, combine the chili powder, cumin, garlic powder, sea salt, and black pepper.
Toss the steak strips and sliced peppers and onions with the spice blend until evenly coated.
Heat the avocado oil in a large skillet over medium-high heat.
Add the steak and vegetables to the skillet, searing for 4-5 minutes until the steak is browned and veggies are tender.
Remove the steak mixture from the pan and wipe the skillet clean.
Place the tortilla in the skillet, sprinkling half with the Monterey Jack cheese.
Top the cheese with the steak and vegetable mixture, then fold the tortilla in half.
Cook for 2 minutes per side until the tortilla is golden and the cheese is fully melted.
Remove from heat, squeeze fresh lime juice over the filling, and slice into wedges.