Heat the oven to 425 degrees.
Layer the cauliflower slices onto a parchment lined baking sheet.
Drizzle the cauliflower with olive oil.
Combine the chili powder, cumin, paprika, oregano and salt and pepper to taste in a bowl.
Sprinkle ⅓ of the seasoning over the cauliflower pisces, and toss to coat well.
Roast the cauliflower until browned and crispy.
Add the ground beef to a skillet over medium high heat, and saute until browned and cooked through.
Drain any excess fat, and sprinkle in the remaining seasoning. Stir to combine.
Place the cauliflower onto a plate or platter.
Top the cauliflower with the meat, tomatoes, onions, black olives and fiesta cheese.