Squeeze the lime. Bring the juice with 100 g of caster sugar to the boil in a large saucepan. Slice the kumquats, add them to the liquid and leave the mixture to simmer gently on a low heat for about 20 minutes. Keep an eye on the pan and add extra hot water if there is not enough water in the pan. Drain and allow to cool.
Heat a dry frying pan and roast the pine nuts on medium heat in about 3 minutes until golden brown. Cool on a plate.
Halve the sweet pepper, remove the seeds and slice the flesh into strips. Slice the tomatoes into thin wedges and the cucumber into strips. Slice the kumquats into thin wedges.
Make a dressing of the olive oil, orange juice, tarragon vinegar, mustard and honey. Season with salt and pepper.
Mix the salad leaves with half the kumquat, the peppers, tomato and cucumber in a bowl. Drizzle with the dressing and divide the duck breast over the salad. Sprinkle with the pine nuts and the rest of the kumquat.
