How to Make It
Drop the onions into lightly salted boiling water for 1 minute; drain. Place the onions in a bowl with the pepper, cumin, garlic, salt, vinegar, and orange zest; add just enough water to cover. Refrigerate until the onions are bright pink, about 3 hours. Drain before serving.
Serve with the onions and an assortment of gutsy, grainy mustards.