Add just enough water to cover 25g of oatmeal and 50g of tuna, microwave for 1 minute and 30 seconds.
Prepare oatmeal and tuna.
Pour water into a pot and bring to a boil.
Once boiling, add oatmeal and stir as it cooks.
Add tuna and chopped green onion, then simmer for 5 more minutes.
Season with salt to taste and finish.