Soak the seaweed in cold water and cut it into appropriate pieces.
Prepare the oatmeal.
Heat sesame oil in a pan and stir-fry the seaweed.
Add tuna (drained) and stir-fry together.
Add water and oatmeal, then bring to a boil.
Reduce to low heat and keep stirring until it thickens.
Season with salt and finish.