Coat beef strips with olive oil, sprinkle with ground cumin and sweet paprika, season well with salt and pepper.

Preheat a non-stick pan to moderately-hot. Keep the heat at moderately high.

Cook the beef in 3 batches.

Cook the first side until the first sign of moisture appears on the uncooked side, turn and cook the other side of the beef strips.

Remove each batch and set aside.

Add onion and capsicum to the pan, cook for 1 minute.

Return beef to pan, stir to warm and squeeze the juice from a fresh lime over the beef.

Remove beef from pan immediately.

Serve beef with warmed tortillas, sour cream, grated cheese and lettuce.