Cut the pork tenderloin into small, bite-sized half-inch cubes.
Heat the avocado oil in a medium skillet over medium-high heat.
Add the pork cubes to the skillet and sear until browned on all sides, about 5 minutes.
Stir in the diced white onion and minced garlic, cooking for another 2-3 minutes until the onion is translucent.
Pour in the tomatillo salsa and season with ground cumin, sea salt, and black pepper.
Reduce the heat to low, cover, and simmer for 10-12 minutes until the pork is tender and the sauce has thickened slightly.
While the pork simmers, warm the whole wheat tortilla in a separate dry pan or over an open flame for 30 seconds per side.
Spoon the pork chile verde mixture into the center of the warm tortilla.
Top with fresh cilantro, fold in the sides, and roll tightly into a burrito.