In a small bowl, combine shallots, vinegar and sherry; let stand for 20 minutes.

Zest 1 orange, avoiding the white pith. Finley chop zest and add to shallot mixture.

Squeeze ⅓ cup juice from zested orange and add to the bowl. Slowly whisk in olive oil and season with salt and pepper; set aside.

Cut asparagus spears in half or fourths, and cook in salted boiling water for 4 to 5 minutes, until crisp tender. Drain well and remove from pan to cool. Toss vinaigrette with asparagus.

Cut ends of remaining oranges, and peel them by cutting down the fruit vertically, following the contours of the fruit. Slice the peeled orange horizontally into ½-inch thick slices. 

Arrange orange slices and asparagus spears on salad plates. Season to taste with additional salt and pepper. Top each serving with 1 tablespoon toasted walnuts. 

Source: California Asparagus Commission