Rinse rice 6 times or until the water is clear.
Transfer rice to a pot and add 1 cup of water or just enough to cover it. Bring to a boil. When it starts boiling lower heat to minimum and cover. Let simmer for 15 minutes. Turn off heat and let it rest.
Dice tuna and set aside in a small bowl.
Add sesame oil to tuna.
Add soy sauce.
Cut open avocado like so.
Assemble bowl. Add rice, place marinated tuna on top and on the side the avocado. Sprinkle tuna with sesame seeds and avocado with salt.