Soak the seaweed in cold water for 10 minutes, then chop it finely.
Chop the onion and finely dice the carrot.
Drain the oil from the canned tuna using a sieve.
Heat sesame oil in a pot and sauté the onion, carrot, and seaweed.
Add the rice and stir-fry together.
Pour in 500ml of water and bring to a boil.
Simmer over medium heat, stirring, until the rice softens.
Add the tuna and season with salt.
Serve in a bowl to finish.