3 tablespoons vegetable oil, such as grapeseed
1 tablespoon toasted sesame oil
1/3 cup rice-wine vinegar
1 large pinch ground white pepper
1 tablespoon Szechuan peppercorns, lightly crushed
1 1/2 pounds Brussels sprouts, trimmed
3 celery stalks, thinly sliced (about 1 cup)
1 serrano chile, thinly sliced (optional)
1 cup cilantro (tender stems and leaves)
In a large bowl, whisk together the oils, vinegar, white pepper, and peppercorns; season with salt. Working over the bowl, separate the Brussels sprout leaves and add them to the dressing. You may need to trim the core more as you get to the center of the sprouts.
Add the celery and chile to the bowl and toss to combine. Let the salad sit about 15 minutes. Add cilantro and taste and adjust seasoning before serving.
Dressing can be made 3 days ahead. Brussels sprout leaves can be separated up to 2 days in advance and stored in an airtight container or resealable bag in the refrigerator. All ingredients except the cilantro can be combined up to 1 hour ahead. Add the cilantro just before serving.