Preheat oven to 205° C (400° F). Ready all the ingredients. Put the orange and lime zest and juice in a bowl. Add the dressing ingredients in order and whisk. Season to taste. Set aside.
Place the pieces of duck leg confit in a roasting pan in a single layer, skin side up. Place in the oven and bake for 12 to 15 minutes. Remove cover. Finish cooking by broiling until the skin is golden brown and very crispy. Remove from oven and let cool on a plate. Debone and shred duck legs. Cut the skin into strips.
Put the peppers, carrots, cabbage, radicchio, basil, mint and shallots in a large bowl and toss with the dressing. Place on a rectangular serving platter. Mix the red cabbage with a little vinaigrette and add to the salad. Arrange the mango slices on top.
Add the shredded duck confit (with crispy skin) and nuts (if using) to the salad. Add pepper and serve.
