Bring water to a boil in a medium skillet over medium heat. Once simmering, add the tempeh slices and cover. Steam the tempeh for 10 minutes. Boiling tempeh helps to reduce or remove any trace of bitterness.
Meanwhile, whisk the tamari, coconut sugar, sriracha, and lime juice into a small bowl. Reserve.
Remove the tempeh from the pan with tongs and place it on a plate to cool. Empty the pan and wipe it to cook the tempeh later.
Dab the steamed tempeh with a clean cloth or paper towel to dry, if necessary. (At this point, the slices can be kept as is, halved, cubed, or crumbled.)
Return the pan to the stove on medium-high heat and pour oil into it. Add the tempeh to the pan and stir. Sauté the tempeh until the pieces are lightly browned, about 3-4 minutes.
Add the ginger and garlic and stir until fragrant enough, about 30 seconds.
Pour the tamari marinade into the pan and stir, peeling off the tempeh (or scraping the brown crumbled tempeh from the bottom) from the pan with a spatula if necessary. Continue cooking the tempeh until the sauce has slightly caramelized and browned more deeply, about 6-7 minutes. Season the tempeh with salt and pepper and stir.
Serve the sticky tempeh with a side dish of your choice, and sprinkle the top with the desired topping.
Placed in an airtight container, this sticky tempeh will keep for up to 4 days.