For the duck, place the salt, coriander seeds, chilli flakes and cardamom pod into a mortar and pestle and pound together. Stir in the oil to make a paste. Rub the spice paste all over the duck.
Heat a frying pan and fry the duck breast skin-side down for 8-10 minutes, or until a lot of the fat has been released and the skin is golden-brown and crisp. Drain off any excess fat into a bowl.
Turn over and fry for a further 3-4 minutes, or until completely cooked through. Remove from the pan and leave to rest for five minutes in a warm place.
For the potato galette, boil the potatoes in a saucepan of salted water for five minutes, then drain.
Heat the oil in a frying pan and fry the potato slices until golden-brown. Season, to taste, with salt and freshly ground black pepper.
For the vinaigrette, heat the orange zest and juice, vinegar, turmeric and sugar in a small pan and simmer until reduced by half and syrupy. Remove from the heat and whisk in the olive oil.
To serve, arrange the potato slices on a serving plate, top with the duck and drizzle over the vinaigrette.