Wash and prep the spinach into bite-sized pieces, and finely chop the chili peppers and tempeh.
Sauté minced garlic and chopped chili in cooking oil to infuse flavor. (If you have fresh ginger or ground ginger, add a little at this step for extra aroma.) Once the aroma comes up, add the chopped tempeh and stir-fry.
When the tempeh is lightly browned, move it to one side of the pan and reduce the heat. Add 1 tablespoon each of soy sauce, mirin, and Yondu. Fry them together until slightly caramelized to create a smoky flavor.
Once the sauce thickens a bit, add the spinach along with 1 teaspoon of vegan stir-fry sauce (or oyster sauce for non-vegan) and a dash of pepper. Turn the heat up and sauté briskly.
Once the spinach has wilted, turn off the heat and serve it over rice.