Whilst the amount of ingredients below are missing, this is because the size of your baguette will determine exactly how much is needed.  Don't vastly overpack the baguette because then it falls everywhere and eating becomes difficult and I don’t overlap my cucumber.

Ingredients
Leftover duck
1 piece of baguette (or demi baguette)
Butter
Hoisin sauce
Mayonnaise
Iceberg lettuceCucumber
1 spring onion

Method
If you would like your duck a little warm then just warm through, either in a dry pan on the stove or briefly in the microwave.

Cut your baguette in half through the middle horizontally and butter.  Put a fairly generous spread of hoisin sauce one side and a light spread of mayonnaise the other.  Put some crunchy iceberg lettuce in and lay down your cucumber.  Top with the duck and scatter over the onions.

Cut the baguette in half and serve.