Preheat oven to 180 degrees C. Wrap tortillas in foil and heat in oven for 8 minutes. Meanwhile, in non-stick frying pan, heat oil over moderate heat. Add onion and capsicum and, stirring occasionally, sauté for 5 minutes or until onion is soft.
Add turkey to pan and, stirring, sauté for 3 minutes or until turkey is no longer pink. Add garlic, cumin, chilli powder, oregano and jalapeño chilli; sauté, stirring, for 1 minute or until mixture is dry. Stir in tomato sauce and coriander.
Heat oven to 230 degrees C. Unwrap tortillas and place on greased baking sheets. Spread equal amount of turkey mixture on each one and sprinkle with cheese. Bake for 8 to 10 minutes or until cheese is melted and tortillas golden. Serve with salsa if desired.