Step 1Blanch the onion in a small saucepan of boiling water for 1 minute. Drain and place in a small bowl. Stir in sugar and vinegar and set aside while making the salad. Drain the onion before stirring it into the salad.
Step 1Place the juices, zest, vinegar and mustard in a small bowl and blend with a small whisk. Slowly add the olive oil, whisking to emulsify. Add salt and pepper to taste. Set aside. Makes about half a cup.
Step 1Trim the cauliflower, discarding the leaves and stalk. Using a mandoline or vegetable slicer set on top of or inside a bowl (to catch little bits of cauliflower), thinly slice the cauliflower by holding the stem end and carefully sliding the cauliflower back and forth against the blade. The pieces should be roughly one-fourth inch thick; adjust the blade depth if necessary.
Step 2In a large mixing bowl, combine the shaved cauliflower, sliced olives, pickled onion and half the chives. Add a generous amount of dressing a little at a time while mixing the salad with a spoon. When the salad is dressed, season with salt and freshly ground pepper.
Step 3To serve, place a few leaves of radicchio, garnished with some leaves of mizuna or other peppery lettuce, on each of 4 salad plates. Divide the salad among the plates. Shell the eggs and cut them in half lengthwise. Place one half, yolk side up, on top of each salad. Sprinkle with the remaining chives.