How to Make It
In a food processor, combine all of the marinade ingredients and process to blend. In a large, shallow dish, pour the marinade over the steaks and turn to coat. Cover and refrigerate overnight. Bring to room temperature before grilling.
In a bowl, combine the olive oil with the anchovies, shallots, parsley, capers, chives and tarragon. Season with salt and pepper and whisk until blended.
Light a grill. Pat the steaks dry and season with salt. Grill the steaks over high heat until medium-rare, about 3 minutes per side. Transfer the meat to a carving board and let rest for 5 minutes.
Thinly slice the skirt steaks across the grain and arrange them on a platter. Drizzle the steaks with some of the salsa verde and sprinkle with the ricotta salata. Serve immediately, passing the remaining salsa verde at the table.