Preheat oven to 400 degrees. Line a large baking sheet with parchment paper or foil and set aside.
In a small bowl, stir together chili powder, cumin, smoked paprika, garlic powder, and onion powder.
Place the cauliflower in a large bowl and drizzle with olive oil. Toss until well coated. Pour the seasoning mixture over the cauliflower and stir until well coated.
Place the cauliflower on the prepare baking sheet in an even layer. Roast for 25 to 30 minutes or until cauliflower is tender. Remove from the oven.
To assemble the tacos, top a tortilla with roasted cauliflower, beans, chimichurri sauce, cabbage, pickled red onions, cilantro, and avocado. Serve immediately.
