In a small bowl, combine the shallots with the vinegars and let the shallots macerate at least 20 minutes. Meanwhile, zest 1 of the oranges (avoid the white pith). Finely chop the zest and add it to the shallots. Juice the zested orange to yield about 1/3 cup and add the juice to the shallots and vinegar. Slowly pour in the olive oil, stirring to mix.
Bring a pot of salted water to a boil. Add the asparagus and simmer until just tender, about 5 minutes. Drain and spread the spears on paper towels to cool.
Cut off the ends of the remaining 2 oranges and peel them by running a sharp knife down the fruit vertically, following the contours. Slice the peeled orange horizontally into 1/4-inch slices. Just before serving, toss the cooled asparagus with the vinaigrette. Arrange the spears and the orange slices on salad plates. Sprinkle with pepper, if you like, and serve immediately.
nutrition information (per serving):
Photo: Maura McEvoy