In a large mixing bowl, toss the cauliflower florets with olive oil, smoked paprika, cumin, garlic powder, and a sprinkle of salt and pepper until evenly coated.
Spread the cauliflower in a single layer on a baking sheet and roast in the oven for 25-30 minutes, or until golden brown and tender, flipping halfway through.
While the cauliflower is roasting, warm the corn tortillas in a dry skillet over medium heat for about 1 minute on each side until pliable. Keep them warm in a clean kitchen towel.
Once the cauliflower is done, assemble the tacos by placing a generous scoop of roasted cauliflower on each tortilla.
Top with black beans, avocado slices, and red cabbage.
Garnish with chopped cilantro and serve with lime wedges on the side for squeezing over the tacos.