Prepare the sauce. Chop the leek and ginger. Place the sesame seeds in a mortar and grind well. In a bowl, add 2 tablespoons sesame seeds, 1 tablespoon soy sauce, 1 tablespoon sugar, 1 tablespoon vinegar, and the chopped leek and ginger. Mix everything well.

In a pot, add the chicken, ginger peel, and green part of the leek. Cover with water and cook over medium heat for 10 minutes. Turn off the heat, flip the chicken, and let it rest covered for 15 minutes.

Cut the cucumber into thin strips. Slice the tomato and chicken.

On a plate, arrange the tomato, cucumber, and chicken. Pour the prepared sauce over the chicken.