In a large frying pan, heat oil then add onion and cauliflower. Sauté, stirring regularly for 4–6 minutes until cauliflower is tender. Add Mexican seasoning and cook for 1 minute. Transfer to a bowl and set aside.
Place tortillas on 2 large baking trays. Brush tortillas lightly with olive oil and prick each several times with a fork. Bake in oven for 6 minutes or until lightly browned and puffed. Set aside to cool.
Top tortillas with cauliflower, chorizo, tomato and lastly grated cheese. Return to oven for 6–7 minutes or until cheese has melted.
Top tortillas with spring onion then cut in wedges. Serve warm.