Combine 10 ounces of the orange juice concentrate with 1 can of warm water in a bowl (reserve the remaining concentrate for the glaze).
Combine the orange juice, peppercorns, garlic cloves, thyme and 1/2 cup salt in a plastic container with a lid. Place the lid on the container and shake to dissolve the salt.
Remove the pop-up thermometer, liver, gizzards and heart from the duck. Cut off the wing tips.
Using kitchen shears, locate the spine at the base of the neck. Cut up the line of the backbone towards the neck cavity. Turn the duck and cut straight towards the rear cavity. Remove the backbone.
Turn the duck over and cut straight down the middle of the breastbone, leaving 2 equal duck halves. To separate the legs from the breast, flip your halves over so the flesh side is facing up at you. Using the knife, make a crescent-shape cut between the leg and the breast.
Line the inside of a plastic lexan or a pot with a zip-top bag. Place the duck quarters inside the
bag and pour the brine over the duck. Seal the bag, ensuring that all the air is removed. Brine the duck for 2 to 2 1/2 hours in the refrigerator.
Bring 1 1/2 inches to 2 inches water to a boil in a large pot. Place a colander into the pot and line the sides of the colander with the duck. Do not stack the duck quarters on each other. Cover and turn the heat to medium-low. Steam the duck for 15 minutes.
Preheat the oven to 400 degrees F. Place a large cast-iron skillet in the oven to preheat on the center rack.
Carefully remove the steamed duck (do not throw out the water) and lay it on a cutting board. Lay your knife flat against the skin and make 3 marks in one direction and then in the other, making an X. Make sure that you are cutting through the skin and not the meat. Score all pieces.
Remove the skillet from the oven, add just the legs skin-side down and cook for 10 minutes.
Remove the skillet from the oven and add the breasts skin-side down and cook 7 minutes more.
Combine the maple syrup, red pepper flakes, remaining orange juice concentrate and a pinch of salt in a small saucepan and bring to a simmer over medium-high heat until the sauce just generously coats the back of a spoon, 3 to 5 minutes.
Remove the skillet from the oven, flip the duck pieces over, brush with the glaze and return the
skillet to the oven to brown the skin until crisp and a deep mahogany brown, 3 to 5 minutes more, or until the legs are 160 degrees F and the breasts register 140 degrees F. Remove the duck from the skillet to a wire rack set inside a baking sheet and loosely tent with foil.
Meanwhile, steam the potatoes in the same water that you steamed the duck over medium heat until they slide off a paring knife when stabbed, 3 to 5 minutes. Drain the potatoes.
Remove and save 1 tablespoon of the fat from the skillet. Heat the skillet on medium-high heat and add the potatoes. Cook, undisturbed, until golden brown, about 3 minutes. Then flip the potatoes and cook 3 to 5 minutes more.
Drain the potatoes on a paper towel-lined plate and season with salt and pepper.
Add the tablespoon reserved duck fat back into the skillet and heat on medium heat. Add the shallots and saute until translucent, about 2 minutes. Toss in the chard and cook until it just barely wilts. Season with the vinegar.
Slice the duck breast thinly on the bias. Serve the duck with the sauteed chard and duck fat fried potatoes. Spoon over additional glaze, if desired.