Heat the grill to medium and season chicken breasts with sea salt and pepper. Grill until cooked though.
Meanwhile, put the green olives, shallots, garlic, parsley, lemon juice and zest in the bowl of a food processor and pulse until all ingredients are diced. Pour olive mixture into a small bowl and stir in olive oil. Season to taste with sea salt if preferred.
Place the grilled chicken on a platter and top with tapenade. Serve.