Heat the oil in a pan. Add the rice and sauté while stirring. Pour in the balsamic and reduce completely. Simmer the rice for approx. 75 mins., adding the stock gradually. Stir in the Crema di Balsamico in the final 15 mins., simmer until all the liquid has been absorbed and the rice is soft, leave to cool.
Place one nori sheet on a bamboo mat or piece of cling film. Spread ¼ of the rice on the nori sheet, leaving a gap of approx. 2 cm along the upper edge. Place ¼ of the strawberries, cucumber and pineapple lengthwise in the centre of the rice, roll up the nori sheet and roll between your hands until everything holds together. Repeat this step three more times. Cut the rolls into 8 equal pieces using a very sharp, wet knife and serve with the lime wedges.