Rub the pork with the ingredients. Microwave at 700 W for 2 minutes. (If you use mentsuyu, just thin with water.)
Cut the cucumber in half, hold the end and peel carefully with a peeler.
Sprinkle with a little salt and mix. After wilted rinse and drain in a colander. Squeeze out the excess water (do not leave the salted cucumber for too long, and work quickly).
Cook the somen noodles following the cooking instruction. Rinse and remove the excess starch. Drain in a colander. Julienne the shiso leaves.
Microwave the pork at 700 W for 1.5 minutes. (Do not cover the container tightly, and just cover lightly with cling film).
Take out from the microwave and add the soy sauce. Mix well and return to the microwave to cook for further 1.5 minutes. (Depending on the container you use, the cooking time may differ, so adjust).
Place the cooked somen noodles on a serving plate. Place Step 4 pork on top. Mix the leftover sauce, cucumber peels and ground sesame seeds. Put on top of the pork (you can mix the shiso leaves at this point).
Garnish with the shiso leaves and sprinkle with the toasted sesame seeds. Pour over the sauce.
On hot days chill Step 6 and before serving.
I put the seasoned meat on top, so the soup itself is diluted. Stock homemade mentsuyu (dashi stock, soy sauce, and mirin in a 4:1:1 ratio) in advance. If this is too strong, thin with water to your liking.
If serving the sauce with udon noodles, double the quantity of the soy sauce and mirin or else it may be too thin.