Drain your tofu, even press it between paper towels to get out moisture. Pour some olive oil in a warm skillet. Throw in about half a block of tofu, chop it up in the pan into small bits, as small as you can get it. Brown the tofu (this can take a while), then throw in your chili beans and about 1/4 cup water.
Mash everything in the pan, it will get thicker, and when there's barely any liquid left, add about 1/4 of the taco seasoning pack to it and mix well. You can add more to your taste.. but don't add the taco seasoning in the beginning or it will end up very salty.
Brush four slices of potato vegan bread with olive oil, broil just a couple seconds til slightly crisp, add a heaping amount of the tofu chili, and there you have a delicious sandwich. I actually got 2 and a half sandwiches out of this, and its very filling, so the serving size might be a little off.
Also, this would make a good taco filling with some tomato, lettuce, and pseudo-cheese! Enjoy!