How to Make It
To make steak, prepare a charcoal or wood fire or both grill to high heat. Spread coals, but maintain medium-high heat (450°-500°) throughout cooking process.
Place salt in a plastic zip-top bag. Crush with a meat mallet or heavy pot. Place beef on a sheet pan. Rub beef with oil. Rub salt into beef, pressing to adhere. Fold tip of beef over to wide side of roast with the fat cap exposed; thread onto a wide, flat metal skewer or sword.
Grab 6 bricks. Make two stacks of 3 bricks wide enough apart to balance your skewer on. You want the top to be about 18”-24” above the surface of the coals (see pic.). Straddle/balance skewer a top bricks. Cook until beef is lightly charred and a thermometer registers 135° in the thickest part of the loin. Transfer meat to a cutting board. Let stand 15 minutes. Slice steak thinly across grain.
To prepare chimichurri, combine all ingredients in a bowl; stir well. Let stand at least 15 minutes. The longer it stands, the more the flavors will meld. Serve with a slotted spoon with steak.