Wash the spinach, wrap it in plastic wrap and microwave. (I have a 'boiled vegetable' auto-setting on my microwave oven, but I think it should be about 1 and a half minutes at 500 W.)
Drain the oil from the canned tuna, and mix all the ☆ ingredients.
Squeeze out the moisture from the microwaved spinach and cut into 4 to 5 cm pieces. Combine with the seasoned tuna and it's done.
I made a komatsuna greens version since we got some as a gift. This was delicious too, and different from spinach.
This version has shiso leaves in it.
Since this has sesame oil in it, don't mix the shiso leaves in; shred it up and use as a topping for a refreshing flavor.
Story Behind this Recipe
I use this combination of flavors a lot, so I thought it would go well with spinach too.
It's delicious when freshy made, but it's even better if you chill it in the refrigerator and allow the flavors to penetrate. You can remove the scum after microwaving if you prefer, but I don't mind it so I don't do anything.