Coat lamb chops with half of tapenade. Grill on medium-high heat for approximately eight minutes. Flip and continue grilling until internal temperature reaches 125°F (medium rare). Cover with foil and let meat rest for half an hour. Divide racks into individual chops. Just before serving, drizzle remaining tapenade sauce over chops.
Put first nine ingredients in food processor and pulse until roughly combined. Drizzle olive oil slowly until desired consistency is reached (should be more like sauce than paste). Taste and add more salt if necessary.