Step 1Season the duck legs on both sides with salt and pepper along with the herbes de Provence. Arrange skin-side up on a rack on a baking sheet and let stand, uncovered, in the refrigerator for 1 hour.
Step 2Heat the oven to 375 degrees. Transfer the duck legs to a shallow baking dish just large enough to hold all of them in one layer. Roast 1 hour.
Step 3Meanwhile, in a small pan, bring the pomegranate juice and chipotle flakes just to a simmer. Remove from the heat and set aside.
Step 4After the duck legs have roasted for 1 hour, carefully drain off the fat from the baking dish and pour the warm pomegranate juice over the legs. Arrange the shallots around the legs. Return to the oven and bake 30 minutes longer, until the meat is tender and the skin is crispy.
Step 5Carefully pour the pan juices through a sieve into a small saucepan. Bring to a boil and cook until reduced by two-thirds. Arrange the greens on a platter or individual serving plates and top with the duck legs. Spoon a little sauce around them and garnish with a good handful of pomegranate seeds.