Soak wooden skewers in water for at least half an hour before skewering meat. 

Slice beef across the grain into wide strips, trimming off fat if necessary. Thread them, accordion style, onto the skewers.

Build the fire and let it die down to coals. 
Just before cooking, drizzle the skewers with olive oil, salt, and pepper. Then lay the skewers over the grill, turning occasionally, until they are sizzling. 

Serve with chimichurri and pickled red onions.