Heat a cast-iron skillet over medium-high heat and add the olive oil.
Add the lean ground beef to the skillet, breaking it apart with a spatula, and sear until deeply browned and slightly crispy.
Stir in the chili powder, cumin, garlic powder, sea salt, black pepper, and minced habanero pepper, allowing the spices to bloom in the beef fat for 1 minute.
Add the black beans and corn to the skillet, tossing them with the beef until heated through.
In a small bowl, whisk the whole egg and egg whites together, then pour into the skillet with the beef mixture.
Gently fold the eggs into the beef over medium-low heat until just set and silky, being careful not to overcook.
Warm the tortilla in a separate dry pan until pliable, then lay it on a flat surface.
Spread the sliced avocado in the center of the tortilla, top with the beef and egg scramble, and sprinkle with feta cheese.
Fold the sides of the tortilla inward and roll tightly into a burrito.
Place the burrito seam-side down back into the hot skillet for 30 seconds per side to seal and create a golden, crunchy exterior.