Make dressing: Whisk all ingredients in medium bowl to blend. Chill until cold.
Make salad: Cook asparagus in large pot of boiling salted water until crisp-tender, about 2 minutes. Transfer asparagus to bowl of ice water to cool. Drain.
Cut peel and white pith from oranges. Using small sharp knife, cut between membranes to release segments. (Dressing, asparagus and orange segments can be prepared 1 day ahead. Cover separately; chill.)
Arrange asparagus spears in sun burst pattern on platter. Place orange segments between asparagus spears. Mound greens in center of platter. Sprinkle salad with basil and tarragon. Top with red onion slices. Drizzle some dressing over. Pass remaining dressing separately.
Courtesy of Gourmet Magazine