Slice the flank steak into very thin strips against the grain and place them in a small mixing bowl.
Season the steak strips with chili powder, cumin, garlic powder, sea salt, black pepper, and lime juice, tossing until every piece is well coated.
Heat a large non-stick skillet over medium-high heat with half of the avocado oil.
Add the sliced bell peppers and red onions to the pan and sauté for 3-4 minutes until they are tender and slightly charred, then transfer them to a plate.
Add the remaining avocado oil to the same skillet and sear the steak strips for 2-3 minutes until they are browned and cooked through.
Wipe the skillet clean with a paper towel and return it to medium heat.
Place the tortilla in the skillet and sprinkle half of the Monterey Jack cheese over one half of the tortilla.
Layer the seared steak and sautéed vegetables over the cheese, then top with the remaining cheese.
Fold the tortilla in half and press down slightly with a spatula, cooking for 2-3 minutes per side until the exterior is golden-brown and the cheese is fully melted.
Remove from the heat, let it rest for one minute, then slice into wedges and serve immediately.