Remove the tendon from the chicken breast, place it in a microwave-safe container, sprinkle with sake and salt, cover loosely with plastic wrap, and microwave at 600W for 2 minutes.

Grate the daikon radish and lightly drain its water. Cut the pea sprouts in half and slice the sudachi thinly. Shred the cooked chicken breast.

Cook the udon noodles according to the package instructions. Add half of the pea sprouts to the boiling water during the last 30 seconds of cooking. Cool the noodles under running water and drain.