Here's a thoughtful approach to sandwich-to-mouth delivery from Eater Jeff in San Francisco (along with Jeff's above demonstration photo):
Little is it known that the perfect sandwich grab is actually not a two handed grab (originally designed to accomplish minimal mass of sandwich acceleration), but a one-handed, open palmed, finger-sprawled and action-ready hand arrangement. The palm is placed on the side near the posterior of the sandwich and the thumb, forefinger, middle finger, and ring finger straddle the tops and bottoms of the sandwich while the pinky finger sprawls directly across and against the back of the sandwich. This retains the sandwich mass with each bite and prevents sauce leakage, which directly translates into more deliciousness, less napkins, and less mess.
As bites progress towards the grabbing hand, the user can then use the other free hand to peel back sandwich wrap and grab juices, chips, or napkins as needed while the grabbing hand can rotate and readjust to accommodate for how the sandwich innards may have shifted during bite.
Here's my take on this grip...
I actually have tried this approach on occasion, and I do think it has its place. It works best when you have large ingredients in danger of falling out, because even something as slim as a pinky finger can hold a larger ingredient in place. However, I don't know that this works as a go-to grip. First, most sandwiches don't have paper, and second, Jeff's claim that the pinkie can hold in sauce is dubious. This grip puts a lot of pressure on the pinky, traditionally the weakest finger.
Despite my reservations, I applaud the amount of thought and consideration Jeff has put into this grip. He is clearly worthy of the Eater moniker! /dan