Make the red wine vinaigrette dressing by combining red wine vinegar, olive oil, brown sugar, and garlic into a container. Shake and taste test for sweetness. Set aside.
Grind the salt, garlic, ginger and juniper berries into a paste using a mortar and pestle. Cover the duck marylands with the paste, and leave to marinate in the refrigerator for 2 hours (or longer if possible).
Preheat the oven to 160°C. Wash the salt mixture off the duck with cold water, and then dry with a paper towel.
Pour the duck fat into a large ovenproof dish, and over a low heat, warm the duck fat until it reaches 120°C. Test using a thermometer. Add the duck marylands to the fat, cover with the lid and place in the oven. Cook for 2 hours or until the duck is tender. Remove the duck from the oven and place on a wire rack to drain and cool.
Approximately 30 minutes before serving, place the potatoes into salted water and boil. Once cooked, drain the potatoes and mash using a potato riser (or normal masher) until smooth. Add butter, and cream (or milk), salt & pepper, and whisk until light and fluffy.
Before serving, heat about 1 cup of the duck fat in a frying pan over high heat. Cook the duck (skin side down) for 3 minutes (or until the skin is crispy), then turn the duck over and cook for another 2 minutes. (Be careful not to overcook the duck at this stage or it will dry out. You just want to warm it through and crisp the skin.)
To another pot of boiling water add the baby asparagus and boil for 3 minutes, or until tender.
In a large bowl add the radicchio, rocket and asparagus. Combine with the red wine vinaigrette to cover the salad.
Plate the salad, mashed potato and duck. Dribble some of the red wine vinaigrette over the dish and sprinkle with black sesame seeds.