Heat the sunflower oil in a large casserole dish set over a moderate heat until hot. Brown the mince in the oil, stirring well to break it up. Add the ground cumin, paprika, Worcestershire sauce and seasoning, stirring well. Remove from the heat once browned all over.
Toss together the papaya and green pepper in a mixing bowl. Add the lime juice and toss well again to mix well. Spoon into disposable ramekins. Spoon the browned mince into the taco shells.
Garnish with the watercress and sliced red onion, then sit in disposable takeaway trays. Serve with the salad to one side.