and cook until no longer pink, 8 to 10 minutes. Remove to a plate and let cool.
Thoroughly combine in a medium bowl:
1/4 cup toasted sesame paste or smooth peanut butter
2 to 3 tablespoons toasted sesame oil (enough to liquefy the sesame paste or peanut butter)
2 1/2 tablespoons light soy sauce
1 tablespoon white vinegar
1/2 to 1 tablespoon hot chili oil, or to taste
1 teaspoon sugar
2 teaspoons minced peeled fresh ginger
1 scallion, finely chopped
Remove the bones from the cooled chicken breasts. By hand, tear the chicken meat along the grain to make rough shreds 2 1/2 inches long by 1/2 inch thick. Place in a serving bowl. Pour the sesame paste sauce over the chicken shreds and mix thoroughly to coat. Place on a small plate:
1 medium cucumber, halved and seeded then cut diagonally into slices 1/4 inch thick
If desired, cover the chicken and cucumbers separately and refrigerate for up to 24 hours. Bring both the chicken and cucumber to room temperature before serving.
To serve, pile the cucumber slices on top of the chicken and serve.