Sandwich shops or stalls can be found on almost every street in Vietnam. They taste great but the selection of fillings is pretty limited (usually meat and a some very simple vegetables).
Ba Mi Lu is a sandwich shop that offers great tasting sandwiches with a bigger selection of fillings at a great price. The menu is quite diverse but to make your choice easier, look at the pictures (they do actually represent the final product). Service is very quick and you can either choose to sit inside (styled like a restaurant in Ho Chi Minh City) or you can choose to take away.
This is a simple fast food restaurant that offers great tasting sandwiches. Definitely worth a try!