Put the mentsuyu and vinegar in a small saucepan, and cook over medium heat for 3 minutes until it comes to a boil. Set aside to cool. Clean the squid by removing the innards. Wash thoroughly. Cut into desired sizes.
Julienne the carrot and cucumber. Shred the lettuce to bite-sized pieces. Combine in a bowl. Pat the squid dry, and coat with flour.
Deep fry the squid in plenty of oil, then, one by one, place the squid into the mixture from Step 1. Set aside for a while to let the flavours blend, mixing from time to time.
Before the squid cools, mix the veggies, squid, and sauce together in the bowl from Step 2. Serve cold. Sprinkle shichimi spice (Japanese 7 spice powder) on top to taste.
Story Behind this Recipe
When we had a company party at an izakaya we frequent, we ordered this dish. I tried recreating it at home. The shichimi makes it spicier and more delicious.
For the marinating sauce, simmer to 1/3 of the original amount of liquid and cool. If you mix the veggies while the sauce is hot, the lettuce will wilt too much. Put the fried squid quickly into the sauce. Don't worry about draining the oil, it's better that way.