I would call it a sort of tuna salad.
Have you tried Kiriboshi- Daikon ( Sun Dried Cut Japanese Radish) . It comes in a package. If there is any Japanese Market around you, probably you can find it there. If you are in Japan, yes, it is easy to find it in " Kanbutsu ( Dry Food) " section.
It is supposed to have good nutrition.... dietary fiber, calcium, vitamin B1 & B2.
a handful of Kiriboshi-Daikon ( Soaked in water for 10 min. ), Canned Tuna ( if it is small can, I would use the whole can. If it is too much for yourself, use about 3 table spoons of tuna ) ,
2 table spoons of wakame ( seaweed. dried. Soak it in the water for 5 min. before use or follow the direction of the package. ) 1 table spoon of Ponzu ( I used Yuzu ponzu--- Japanese lemon's. If you don't have it, use lemon juice and soy sauce. )
1. Cut Kiriboshi daikon into 3 cm. or bite size.
2. Mix all the ingredients.