Chinese Chicken and Cucumber Salad (凉拌鸡丝)

Poach the Chicken: In a medium saucepan, combine chicken legs, ginger, onion, black peppercorns, bay leaf, and Sichuan peppercorns, if using. Add enough water to cover the chicken by 1 inch. Bring to a gentle simmer over medium-high heat, then reduce heat as needed to maintain the simmer. Cook until the thickest part of the thigh registers 150°F (66°C), 15 to 25 minutes, depending on the size of the chicken legs.

Turn off heat and let chicken steep in the hot cooking liquid until the thickest part of the thigh registers 165°F (74°C), about 10 minutes longer. Transfer chicken to a plate and let stand until cool enough to handle. Strain and reserve poaching liquid for another use, if desired.

Prepare the Cucumber: Meanwhile, place the whole cucumber horizontally on a cutting board. Starting at one end, slice cucumber diagonally into 1/8-inch-thick ovals, adjusting the knife angle as needed so each oval is about 2 1/2 inches long. Gather the ovals in a long, slightly overlapping line, then cut lengthwise into 1/8-inch matchsticks.

Transfer the cucumber matchsticks to a medium bowl. Sprinkle with kosher salt and toss to combine. Let stand for 10 minutes. Press the cucumber firmly over a strainer or wring it in paper towels or a clean kitchen towel to remove as much excess liquid as possible. Discard liquid. Transfer cucumber to a large mixing bowl and add scallion greens and cilantro.

Make the Dressing: In a medium heatproof bowl, combine garlic, reserved scallion whites, sesame seeds, and chiles, if using. In a small saucepan, heat oil over medium-high heat until shimmering and just beginning to smoke, about 2 minutes. Immediately pour hot oil over the garlic mixture and let it sizzle vigorously. Stir in sesame oil, soy sauce, black vinegar, and sugar until the sugar dissolves.

When the chicken is cool enough to handle, remove and discard skin, bones, excess fat, and tendons. Pull meat into thin shreds. The pieces do not need to be threadlike, but they should be thin enough to catch the dressing. Add shredded chicken to the bowl with the cucumber, scallion greens, and cilantro.

Add about half of the dressing (about 1/4 cup; 60ml) and toss well. Taste and add more dressing as needed. Serve cold or at room temperature.