- Peel the oranges with a sharp serrated knife. (To do so, cut off the polar ends, then slice down the sides to get all the skin and pith removed.) Slice the oranges into thin rounds, removing and discarding seeds as you go. Place the slices in a bowl and set aside.
- Shortly before serving, divide the watercress among 4 to 6 serving plates, separating the sprigs, so they are not all in one clump. Arrange the orange rounds on the watercress, and then scatter radish slices on the oranges. Sprinkle with minced onion, then ladle on a little of the vinaigrette. Scatter the walnuts, grind on some black pepper, and serve right away.
Orange-Shallot Vinaigrette
- Combine the shallot, zest, orange juice, honey, vinegar, and salt in a small bowl. Mix steadily with a small whisk, first to combine, then as you drizzle in the oil.
- Keep whisking for a minute or so after all the oil is in. Taste to possibly adjust honey and salt.
Note: You can slice the oranges up to several days ahead of time, if you store them in a tightly covered container in the refrigerator. They will emit some juice while sitting and you can use it for the vinaigrette. Also note that you can zest a couple of the oranges before peeling and slicing, also for use in the vinaigrette.