Thinly slice the shiso leaves and ginger.

Pat the mackerel fillets dry with paper towels and sprinkle both sides with salt. Let sit for 5 minutes, then pat dry again.

Heat salad oil in a frying pan over medium heat. Place the mackerel skin-side down and cook for 3–4 minutes until the skin is golden brown. Flip and cook for another 3–4 minutes.

Mix sugar, salt, and vinegar in a bowl to make sushi vinegar.

In another bowl, combine the cooked rice with the sushi vinegar, mixing gently. Add the sliced shiso leaves, ginger, and sesame seeds, and mix.

Place the mackerel skin-side down on a sheet of plastic wrap. Add half of the rice mixture on top, wrap tightly, and shape into a sushi roll. Repeat for the second roll.