Slice the tomato and cucumber into thin slices, set aside. Chop the green onions, separating the white and green parts.
Cut the chicken breast into bite sized pieces. Using a mallet or a rolling pin, flatten the chicken to tenderize. In a separate bowl, marinate the chicken in sake and salt for 5 minutes.
Pour plenty of water in a pot and bring to a boil.
Pat dry the chicken using paper towels and then coat with potato starch, brushing off the excess. Add chicken into the boiling pot and boil for several minutes.
Once the chicken is boiled, transfer the chicken to ice water to cool down.
To make the sauce, add ponzu vinegar, sesame oil, and the white part of a green onion inside a Zip Loc bag. Add in the chicken from step 6 and marinate for 5 minutes. The crystal chicken is complete!
Pour the soup base and 2 ½ cups of oat milk in a bowl, mix well.
Boil water in a pot and follow the package instructions to cook the noodles. Once the noodles are cooked, rinse with coldwater and drain well.
Add the chilled noodles to the soup from step 7 and top with crystal chicken, sliced tomatoes, and sliced cucumbers. To finish, add chopped green onions. Enjoy!