Maybe I'm a clueless jackass, but I've made sandwiches before, and I've seen sandwiches made in sandwich shops before, and I can't imagine this "training" taking longer than a shift. The training that isn't directly related to sandwiches, e.g. how to stock the cooler and where the dumpster is located, is likely to vary from shop to shop. Most hiring shop managers are going to look more closely at how long one has held jobs than whether those jobs were with a competing sandwich chain.
I worked at a Jimmy Johns for a few months. They make the sandwiches in a very specific way to optimize for speed. The average time between order and handoff to a customer was about a minute during busy times.
