- 1 medium red onion, halved through root end, thinly sliced
- 1/2 cup fresh lime juice
- Kosher salt
- 1/4 cup cilantro leaves with tender stems, coarsely chopped
- 2 teaspoons sumac
- Combine onion and lime juice in a small bowl. Season with salt and toss. Let sit, tossing occasionally, at least 20 minutes.
- Just before serving, drain onion and toss with cilantro and sumac.
- Onion can be pickled 3 days ahead. Cover and chill.