In a small bowl, combine red onion and vinegar - set aside (see notes).
Add peanuts to a food processor and pulse until finely chopped (less than 1 min - any more and you may end up with peanut butter!) - alternatively chop by hand using a sharp knife.
On a large plate, add paprika, powdered garlic, cayenne pepper and salt to crushed nuts, mixing to combine.
Rubs steaks all over with ½ tbsp. olive oil, then add steaks to crushed nut mixture, pressing to coat well.
Heat 1 tbsp. olive oil in a large non-stick frypan (I use the pan from the flatbread, just carefully wipe out any remaining flour) over medium high heat.
Add steaks and turning once, fry to your liking - this will depend on how thick your steak is and how you like it done (rare, medium rare, well done etc) - add more oil if needed.
Remove to a plate and cover loosely with foil to rest.
Combine remaining 4 tablespoon of yoghurt and lemon juice and set aside.
Combine mint, parsley, tomatoes and onion mixture, mixing to combine and set aside.
Take one flatbread and brush the presentation side lightly with melted butter..
Slice steak - reserving any juices/crushed nuts from the plate.
Spread 1 flatbread with 1 tbsp. of yogurt, top with steak (drizzle over reserved juices/crushed nuts) and salad.
Serve immediately.