Preheat your grill to medium-high heat (around 400°F). If using an indoor grill pan, heat it over medium-high heat.
In a large bowl, toss cauliflower florets with olive oil, chili powder, cumin, smoked paprika, garlic powder, salt, and pepper until evenly coated.
Place the seasoned cauliflower on the grill or grill pan. Cook for 4-5 minutes per side until you see nice char marks and the cauliflower is tender but still has some bite.
While the cauliflower cooks, warm your tortillas on the grill for about 30 seconds per side.
Assemble your tacos by placing grilled cauliflower in each tortilla, topping with sliced avocado, diced red onion, and fresh cilantro.
Serve immediately with lime wedges and hot sauce on the side.