This salad is quick and easy to make. It takes less than an hour to prepare, and about 30 minutes of that time is waiting for the duck breasts to warm up at room temperature, so they're not cooked straight out of the fridge. Make sure the mixed salad greens have some radicchio or endive or another type of bitter green, which helps to balance the fattiness of the duck breasts.
Take the duck breasts from the fridge and dry them with paper towels. Use a sharp knife to score the duck skin, cutting in a crosshatch pattern at 1cm (7/16in) intervals, taking care not to cut into the flesh. Leave at room temperature for 30 minutes.
Wash the salad greens and dry them. Thoroughly combine the salt with the five-spice powder.
About 15 minutes before you want to serve dinner, spread the salt/five-spice mixture over the entire surface of the duck breasts, to coat them evenly but lightly. Shake off the excess (this is important, or the duck will be too salty); discard any leftover salt/spice mixture.
Lay the breasts skin-side down in an unoiled skillet, preferably cast iron. Place the skillet over a high flame. After about a minute, the duck will start to sizzle. When you see the fat starting to render - it will ooze out around the edges of the breasts - set the timer for five minutes and lower the heat to medium-high. After five minutes, flip the breasts over, turn off the flame and let the meat cook in the residual heat of the pan. After about three to five minutes (for medium-rare; adjust the time as needed if the breasts are larger or smaller, or if you like the meat more well done), place the breasts on a cutting board and leave to rest for five minutes while preparing the salad.
Put the salad greens in bowl. From the pan used to cook the duck breasts, pour off all but about 60ml of the fat (if there's not enough fat, add some olive oil to the skillet). Warm the fat over a medium flame, then use a whisk to stir in the red wine vinegar. Whisk in a few drops of honey, then dip a salad green into the mixture and taste to see if the seasoning is correct; if necessary, add more vinegar or honey.
Immediately pour the hot dressing over the salad greens, to wilt them slightly. Mix well then divide the greens between two plates.
Cut the duck breasts against grain into slices about 5mm (¼ in) thick and place them on the plate. Sprinkle lightly with sesame seeds and serve immediately.