- Heat a cast-iron skillet on the stove with a little olive oil.
- Grind pepper and salt onto the whole duck breasts.
- When the pan is hot, sear the duck on each side for just a few minutes.
- Cook to medium-rare. You can slice the meat in the pan if you like and cook a little longer so they're not raw in the middle—just make sure to keep the meat pink. Once you hit medium, the duck loses a lot of flavor and becomes tough.
- While the duck is cooking, chop your cilantro, dice the onions, and slice the radishes. The radishes don't have much flavor, but they add a killer crunch.
- Slice the duck (if you haven't already). Keep it in the skillet so it doesn't get cold.
- Warm up the tortillas. Toasting each side right over the gas stove burner for a few seconds works best.
- Add your ingredients however you like. Eat immediately, it cools off quickly.