Preheat a pan over medium/high heat with some olive oil.
Put the meat in the pan and add salt and pepper.
Let it fry for 3-5 minutes on each side (depending on how rare you like your meat).
Meanwhile preheat a nonstick pan over medium heat.
Fry the tortilla bread on each side until slightly browned.
When the beef is ready, slice it into thin slices.
Put the tortilla on a plate.
Add 2-3 slices of beef, top with crumbled feta cheese and pickled red onion.
Add lime wedges on the side.