Smoked Salmon, Asparagus, and Potato Cake Canapés

• ¼ lemon
• 8 asparagus spears, trimmed
• ½ recipe Simple Salmon Mousse or <

To cook the asparagus, bring 4 cups salted water to a boil in a wide saucepan. Squeeze the lemon juice into the pot, then add the rind to the water (the lemon prevents the asparagus from discoloring during cooking). Add the asparagus and cook for 4 to 5 minutes, until tender but still firm in the cente