Reduce the heat slightly and place the kebabs onto the baking paper. Brush some more glaze over the kebabs while they cook on one side for about a minute. Turn the kebabs, brush on some more glaze and cook for a further minute. Continue until they have cooked evenly on all sides. After approximately 6 minutes, when the tuna is still a little pink in the middle, remove the kebabs, cover with foil and allow them to rest. Serve the kebabs with the remaining cranberry glaze on a bed of rocket with steamed green beans drizzled in a good quality olive oil.