Drain tuna and add to a bowl. Mix in kewpie Mayo, sriracha, and coconut aminos to taste.
Cut the seaweed halfway up, starting at the base.
Add rice to the bottom right square of the sheet.
Add tuna mixture to the upper right square of the sheet. Top with spicy mayo, sushi sauce, and green onions.
Add cucumber slices to the upper left square.
Add mashed avocado to the bottom left square.
Fold the rice up to flip onto the tuna, then fold it to the left over the cucumbers, and down toward the avocado to create a wrap.
Enjoy!