I just ran across Kim's Sandwich, which is located on Winter Street (between Tremont and Washington right across from Park St. station) in a hole in the wall "food court" that also contains Falafel King and a bad Chinese take-out place. He's been open for about a week.
Anyway, I had the "bean curd" sandwich. Overall, very good. The sandwich contained a braised tofu (owner said he cooks the tofu himself) with shredded carrot, shredded daikon, lightly pickled cucumber, cilantro (not stemmed like Mix Bakery usually does), hot peppers (seems like jalapeno or serrano, not bird peppers -- not minced, but in bigger slices), with a slathering of mayo (yellowish in color) and a bit of soy sauce (probably maggi sauce). He warmed up the bread. The bread was the French roll, a bit more "crusty" than Mix Bakery's. I like Mix's a bit more.
The prices were $2.25 for the bean curd (he also has
"tofu" as an option, which is sliced into strips rather than the "bean curd's" flat rectangles). The chicken cold cut was $2.50 and the bbq beef was $2.75, but I did not try either. Overall, I might like Mix Bakery's tofu slightly more, but I'm really psyched that I don't have to walk from the Financial District to Chinatown to get my bahn mi fix!