When I worked at a deli, one of my jobs was to shred the lettuce for sandwiches and salads. It always seemed to take me forever to get it all done with a chef's knife, and the results weren't always very good. I wanted to have very finely shredded lettuce, but I still had large chunks from time to time.
It finally dawned on me that I had the perfect lettuce shredder right in front of me. I cleaned off the meat slicer and set the blade to maybe 1/8th of an inch at most. After taking out the core and pulling off the outer leaves, I'd run the heads of iceberg lettuce against the slicer blade and put the results in a bucket of ice water. The slicer did a much better job of shredding that lettuce than I ever could.