Bring a pot of lightly salted water to a boil and fill a large bowl with ice water. Trim off the woody ends of the spears. Blanch the asparagus in the boiling water for 3 minutes. Dump the asparagus in the ice water to stop them from overcooking and getting mushy. This also keeps the bright green color.
Whiz the citrus juices, zests, mustard, salt, and pepper together in a blender. Gradually drizzle in the oil until the vinaigrette thickens. Drain the asparagus and arrange the spears on a serving platter. Pour on the vinaigrette, garnish with fresh mint, and weâ€™re home.
Edited: October 15th, 2009