i dont know. i made this up and it tasted good.
1 can tuna, drained
1 can water chestnuts, optionally chopped
1 green onion, chopped
you can either then put in some chopped raw green beans, or chopped cucumber.
throw the above in a bowl and mix. throw in a few dashes of rice wine vinegar. then a few dabs of soy sauce. then as much wasabi paste as you can handle, which for me lis, like, half a tube.