Recently when we visited Japan, my wife had a "gunkan" 軍艦 sushi which was topped with tuna salad (canned tuna dressed in mayonnaise) from a chain take-out only sushi store at a home party. I did not try it but, according to my wife, it was unexpectedly good, especially the combination of mayo, nori, and sushi rice. While we might agreed that mayo and sushi rice was a good combination on principle we both balked at the use of canned tuna. So, instead, I used a frozen yellowfin tuna block. As I posted several times, this frozen tuna block is my emergency sashimi ration and requires some additional treatment to make it palatable. So this is an ideal tuna to use.
After thawing the tuna block, I did my usual "Yubiki" 湯引き treatment and then made half into "Zuke" 漬け. I made one quarter into "Namerou" なめろう, I used half of the Zuke in "Yamakake" やまかけ. So, I made these hand rolls from a quarter each of Yubiki and Zuke tuna.
For the tuna mayo hand roll; I cubed the yubuki tuna. I dressed with mayonnaise mixed with the marinade from making Zuke (or soy sauce, just a splash) and Sriracha for kicks (to your liking). I also added finely chopped perilla leaves.
For the tuna zuke hand roll; I cut slices of the zuke tuna in half to make long strips.
I made sushi rice as per usual. I then cut the nori in half to make long rectangular pieces. I passed the nori over a gas flame several times to make it crispy and to give it a toasted aroma.
I arranged the components of the hand rolls in order so that we could assemble them quickly (Actually I assembled and handed it to my wife).
I placed the rectangular nori sheet at an angle on my open palm with the top corner in the 12 o'clock position, just hanging over my fingers. I placed the sushi rice on the upper 1/3 of the nori, added a spoonful of the tuna mayo. Wrapped it up to make a cone (see below).
For the second roll, I added Ikura or salmon roe as well since I had it.
For zuke hand roll, I place two strips of zuke tuna, a slice of cucumber and perilla leaves. I forgot to add wasabi this time.
I have to agree with my wife that the tuna mayo hand rolls were pretty good. This combination of tuna and spicy mayo is not unusual in any American sushi bar especially as a roll but we never tried it. So this is an eye opening experience and now we have another way of making this low-quality block of frozen yellowfin tuna sashimi palatable. Problem is my wife is talking about egg salad sushi.
P.S. After this post, I came across an article describing the first recorded use of mayo in sushi (in Japanese). According to this, it was invented by the sushi bar in Miyazaki 宮崎 called "Ippei" 一平 in Shouwa 41 nen 昭和４１年 (1966). It was a roll with shrimp, lettuce and mayo and details are in the web site of this sushi bar (in Japanese).