Nori leaves are made by grinding them into the water of fresh Porphyra type seaweed, then drying the resulting mixture in moulds. Nori leaves are often used in traditional Japanese cuisine, particularly in sushi and maki.
To make maki: Flatten a Nori leaf. Cover it with sticky Japanese rice. Put any ingredient you like along the middle of the leaf: fish (salmon, tuna) cucumber, avocado… Roll up the leaf and cut it into six maki. Finally, enjoy!