We make burritos this way, using black beans instead of refried, and adding some rice as well. To wrap it, I make sure all the filling is spread in a rectangular shape, then I fold in the short ends of the tortilla. Fold over one side, then roll the entire tortilla on top of the last side. This process keeps any from squishing out, and you end up with a pretty burrito.
This is how I make mine as well but I use ranch style beans. So good and so easy.
This is just the way I make our burritos except I add avocado slices. Yummm