Mix the mustard, honey, white wine vinegar and salt together in a bowl until a creamy sauce is formed. Add the finely chopped onion, stir and let steep for 5 minutes.
Add the olive oil and stir vigorously again.
Pour the dressing over the asparagus and let it steep for one to two hours, covered.
Before serving, carefully turn the asparagus stalks and garnish with the chopped egg and chives. Sprinkle with coarse pepper as desired.