Method:
In the bowl of a food processor, blend together lentils, olives, tuna and garlic until smooth. With an on-off motion blend capers, mustard, lemon zest, lemon juice, salt and pepper. While the motor is running, slowly add reserved liquid and olive oil. Pack into a crock and pour extra olive oil on top. Cover and refrigerate for a few hours or overnight to allow the flavors to meld.