Make tapenade: Combine olives, 1/4 cup oil, cilantro, capers, garlic and vinegar in a food processor and process until blended. Transfer to a bowl.
Heat a gas grill on high. Rub steak with 1 Tbsp. olive oil, sprinkle with salt and grill, turning once, 8 to 10 minutes total for medium-rare. Transfer to a cutting board, tent with foil and let rest 5 minutes. Slice against the grain. Serve with tapenade spooned on top.