Place the coconut oil in a pan over medium heat. Add the onion and cook for 1 minute, stirring frequently. Add the garlic, bell pepper, mushrooms, salt, and pepper and cook for 3 minutes, stirring frequently.
Add the cauliflower, chili powder, cumin, and chipotle chile powder and cook until the cauliflower is just tender, about 10 minutes, stirring frequently. Add the lime juice and cilantro and mix well. Lower the heat to low to keep filling warm.
Warm the tortillas briefly by placing them one at a time in a dry sauté pan over high heat, flipping with tongs until just warmed through.
Place the mushroom cauliflower filling inside the tortillas, top with your condiments of choice, and enjoy!