The basic set-up for the sandwich is the following; bread, protein (meat/tofu), pickled vegetable, spice, mustard/mayonnaise (optional), herbs (optional), plus much more. Below are the different parts that I cooked to create my sandwich.
For the tofu portion, I found a recipe here. Seems like the entire site is focused on the Banh Mi so you can really research the different possibilities. Letting the tofu marinade was great because it absorbed a lot of the flavor in the marinade and it cooked very easily due to the oil it has soaked up.
For the pickled portion, I made a simple vinegar slaw with radishes and carrots. I boiled about a cup of vinegar, 1/2 a cup of sugar, some onions, and a mixture of spices (Turmeric, salt, mustard seed). After the onion softened I poured it over the carrots and radish mixture. Very good.
I was going to make my own mayonnaise but I did not get to it, but I had made my own bread earlier that day. The yeast was a little dead but they still had a little metabolism left.
Finally, I added a fried egg to the sandwich. Fried eggs fit into the category of "never a bad idea to add to a ________". It held true for this meal.