Mix all the vinaigrette ingredients together and stir to incorporate. Allow at least a ½ hour for flavours to meld.
You may choose to cut away strips of the cucumber peel, leaving some green contrasting peel. Quarter cucumber lengthwise. Run a small spoon the length of the cucumber to remove the seeds. Cut cucumber into ½ " cubes.
Cut the fleshy faces off the mango. Peel off the tough outer skin. Cut pulp into ½" cubes.
Just before ready to serve, halve avocados, remove pits and scoop the flesh out of the peel. Cut in to ½" cubes.
Toss cucumber, mango and avocado (and shrimp if using) with the creamy dressing. Serve on Bibb lettuce leaves if desired.
Notes
Nutrition does not include optional lettuce or shrimp.