Heat the oil in a non-stick or well-seasoned cast-iron skillet.
Place the slices of tofu in a single layer and cook until lightly browned on both sides.
Remove from the pan and to a chopping board. Cut into 1/2-inch cubes or smaller, if you prefer.
To the pan, add the carrots and onions and season with some salt and pepper (don't over-salt. You'll be adding the tamari later).
Stir fry until the onions start to sweat. Cover the pan and let the carrots and onions cook over medium-low heat for about 5-8 minutes until the carrots are tender but still crunchy.
Add the tofu cubes back to the pan and dump in the glaze. Give everything a good stir but don't mash down too hard on the tofu-- be gentle or you will break it.
Let the glaze reduce over medium-high heat until it coats all of the vegetables and the tofu. The mixture should be quite dry.
Turn off the heat.
To serve, place the tofu-carrot filling in a taco, top with some salsa and some guacamole, and serve.