Unwrap the ducks and allow them to sit at room temperature for 20 minutes. With a fork, prick the skin without piercing the meat. This will allow the fat to drain off while the ducks cook.
Meanwhile, in a very large stock pot which can hold the 2 ducks, heat the chicken broth with 1 tablespoon of kosher salt until it boils. Add the ducks very carefully and bring the stock back to a boil. If there isn't enough stock to cover the ducks, add the hottest tap water to cover. If the ducks float to the top, place a plate on top to keep them immersed. When the stock comes back to a boil, lower the heat and simmer the ducks in the stock for 45 minutes.
When the ducks are finished simmering, skim off enough duck fat from the top of the stock to pour a film on the bottom of a 14 by 18 by 3-inch roasting pan. This will keep the ducks from sticking when they roast. Carefully take the ducks out of the stock, holding them over the pot to drain. Place them in the roasting pan, pat the skin dry with paper towels, and sprinkle with 1 teaspoon of salt and the pepper. If you have time, allow the ducks to sit at room temperature for 30 minutes to allow the skin to dry.
Meanwhile, preheat the oven to 500 degrees F. (Be sure your oven is very clean or it will smoke!) Roast the ducks for 30 minutes. Remove from the oven and allow them to rest, covered with aluminum foil, for 20 minutes. Serve warm.