A sandwich with burrito ingredients. Strictly speaking, a tortilla must not be used as the "bread" as this would make the meal a wrap. Typical Mexican ingredients are used which may include rice, beans, cheese, etc. The bread may be any that is traditionally used in the making of a sandwich. A sandurrito is not a torta as a torta uses a bread that is more similar to a tortilla that is flat and round and does not use yeast as a rising agent.
"All we have is bread and Mexican food. Let's make a sandurrito!