After frying the tulingan (skipjack tuna), remove the whole fillet from the bones, then cut it in half lengthwise. Set aside.
Make teriyaki sauce by combining all the ingredients listen above and let it simmer for about 2 minutes. Add the slurry and let it simmer for around 1 minute to thicken.
Place the fried tulingan fillet in the teriyaki sauce, marinate for 15 minutes.
Combine the mirin and sugar in the newly cooked rice. Mix well, then season to taste with salt and pepper. Cover it with cling wrap and set aside.
If you don't have a sushi rolling mat, you can use a cling wrap instead. Place a sheet of cling wrap over your chopping board.
The wrap should be bigger than your nori sheet, rough side up, then place a a sheet of nori on the cling wrap and place a thin layer of rice over the nori, leaving 1 inch space from the top.
Place the sliced marinated tulingan fillet over the rice, then roll it using the cling wrap to help you roll it perfectly.
Take out the plastic wrap and cut it into 8, using a wet knife every slice to prevent the rice from sticking to the knife.
Serve with soy sauce and wasabi.