Well, technically it's a wrap, not a sandwich.
1. 1 whole grain wrap (the kind at the story especially made for sandwiches)
2. couple spoons of peanut butter
3. right at a spoon full of nutella
4. spread peanut butter and nutella on wrap - IMPORTANT: spread it all the way out to the edges, so that when you wrap it up that first bite has everything in it
5. slice up a ripe banana, and line up as many slices as you can fit across, just one row
Seriously, I just downed one of these badboys and it was great.