Heat the oil in a frying pan, fry the onions until transparent, add the mince and continue cooking for approx. 4 mins., stirring occasionally. Reduce the heat. Add the vegetables, cover and simmer for approx. 5 mins. Season with chilli powder, paprika, salt and pepper. Divide the filling among the tortillas, garnish each with 1 tbsp of sour cream and loosely roll up.