Whenever I'm in Munich I drop by this place. Very conveniently located right outside the main train station. Walk towards tracks 27-36 (which are shorter than the others), exit the train station there and turn left.
They have several vegan dishes to choose from, but the best is the vegan Döner. Several vegan sauces are available and they are all great. I like the Tzaziki sauce best though.
Staff is very friendly and helpful. It's just a bit weird that they once tried to convince me to have the standard yoghurt sauce with the vegan döner. That one is not vegan but they insisted it was better... Only happened once though. Usually they are very happy to accommodate vegan diners.
If you go more often make sure to get the rebate stamp card!