After playing with tempeh shapes, from crumbles to shreds to slices, I have found what works for me. The pieces are small enough to soak up tons of tacoriffic tastiness without having that ground-beef feel, which creeps me out to no end.
For two very hungry people (with a good chance of leftovers), I use one block of LiteLife tempeh. This one is Garden Veggie. Cut in half lengthwise then into thin slices.
Add the tempeh to a couple of tablespoons of oil and about a quarter cup of water. Add your favorite taco seasoning now—what you’re doing is steaming the tempeh at the same time you’re very quickly marinating it.
This photo (blurred by steam) is the tempeh after the water is pretty much soaked up/evaporated away. The tempeh will now start to brown/blacken a bit. Add a little extra oil if it starts sticking. At this stage it’s perfectly edible, but I like to let it brown a while. Be careful when you’re stirring it around because it’s pretty tender (if you want to avoid crumbles).
As soon as the tempeh finishes cooking, I heat the tortilla right on the burner—sometimes without burning it or leaving little bits of tortilla stuck to the burner.