Preheat the oven to 200°C, 180°C fan, gas 6. Put the duck breasts on a baking tray and roast in the oven for 25 minutes until cooked. Drain off the oil and allow to cool.
Meanwhile, heat a griddle pan until hot and brush the aubergine slices with the oil. Cook in batches on a low heat for about 5 minutes on each side, or until chargrilled and just tender. Set aside.
When the duck is cold, shred into bite-size pieces. Put the soy sauce, honey and lime juice and zest into a pan and bring to the boil. Add the shredded duck and stir well to coat. Cook for 3-4 minutes until it is heated through.
To assemble the rolls, divide the duck between the slices of aubergine, scatter with the sesame seeds and top with the spring onion and cucumber. Roll up and secure with cocktail sticks. Serve immediately.