Fry the mince in a large, nonstick frying pan for 8–10 minutes until it becomes golden brown. Add the cinnamon and pine nuts and cook again for 1 minute. Remove from the heat.
Place the warm naan breads on a chopping board and, using a rolling pin, firmly roll to flatten.
Mix the hummus with half the mint leaves, then spread in a thick layer over the warmed naans. Spoon over the crispy lamb, then scatter over the shredded lettuce, if using, and the remaining mint leaves. Tightly roll up and secure with cocktail sticks. Serve immediately, or wrap tightly in foil to transport.