Cook shrimp in boiling water until just cooked through. Do not overcook. Cut asparagus into bite size pieces and blanch for a minute. Let both cool and set aside.
Slice onion very thinly. Cut avocado into 1/2 cubes.
In a medium bowl, whisk all the ingredients for the dressing together.
Add cooled shrimp, asparagus, onion, and avocado into the dressing, and coat well. Serve on lettuce leaves.