FILL a medium saucepan halfway with water and bring to a boil. Break off and discard tough ends from asparagus, then peel bottom third of stalks with a vegetable peeler. Add asparagus to boiling water. Boil until tender-crisp, 5 to 6 min. Using tongs, remove asparagus from water and immediately plunge into a bowl of cold water. Drain and pat dry. MELT butter in a small pan over medium- high. Skim off and discard foam. Pour butter into a measuring cup, leaving white solids behind. Whirl egg yolks with lemon juice, hot water and salt in a blender for 1 min. Slowly pour hot butter through hole in lid, whirling until thickened, about 1 more min. Spoon over asparagus. Sprinkle with chives and fresh pepper.