Heat a large skillet over medium-high heat. Add avocado oil, then add the beef, mushrooms, zucchini, kale, onion and garlic. Then add the salt. Cook for 5 minutes, stirring occasionally, until the meat begins to brown and the vegetables soften. Add the chili powder. Cook for an additional 2 minutes. Add the water, reduce the heat, and let cook for another 5 minutes, until the beef is cooked.
Place the taco shells in the oven for 8 to 10 minutes to warm them. Assemble each taco by adding in 2 tablespoons of the meat, kale and mushrooms. Top with onions and zucchini and add 1 teaspoon of chipotle sauce.