Heat the oil in a pan and cook the shallot and chorizo for 5 minutes until the shallot is softened. Stir in the chicken and tomatoes, Remove from the heat. when chicken is cooled, shred with a fork.
Put pieces of the chorizo and chicken onto the tortilla. Either put the mayonnaise or bbq sauce on the tortilla first or last. Put salad vegetables onto tortilla and wrap the tortilla into a parcel.