Open the hiyashi chuka sauce packet and pour the sauce into a small bowl. Pour lemon juice and mix. Chill the sauce in the fridge. The yuzu lemon sauce is ready!
Slice the tomato, lemon, and cucumber. Slice the lettuce to wide strips.
In a pot, add in water, sake, ginger slice, and green onion. Bring the water to a bowl. Once the water starts boiling, add in the chicken breast and cook over low heat (10 minutes). Once the chicken is thoroughly cooked, remove the chicken from the pot to cool down. Once the chicken breast is cooled down, shred the chicken by hand. Set aside.
Boil plenty of water in a pot and follow the package instructions to cook the noodles.
Once the noodles are cooked, rinse with cold water and drain well.
Place the noodles in a bowl/plate and top with sliced tomatoes, lemons, cucumbers, and shredded chicken. Before serving, swirl in the yuzu lemon sauce, and enjoy!