Seattle has many excellent banh mi restaurants. To me, you have to start with a mix of slivered carrots and daikon radish pickled in sugar and salt (do chua). Then, you need a small French roll. Slice it, toast it (if you like) then add mayonnaise, cilantro, thinly sliced cucumber, thinly sliced jalapeno peppers, some kind of meat, and (optionally) Maggi sauce.
For those who don't know, banh mi are Vietnamese sandwiches. Why would the Vietnamese be serving Parisian-style sandwiches? Don't forget Vietnam was once a French colony ..