Cut cooked artichokes in half and remove choke. Place lemon slice in the place of hollowed out portion of the artichoke and secure with a wooden skewer. Rub entire artichoke and lemon slice with olive oil.
Place artichokes on hot grill and cook until the lemon begins to char (flipping artichoke often).
Serve warm off the grill and use lemon to squeeze on artichoke leaves.