Make a small hole in the extra skin on the chicken legs and poke the end of the drumsticks through to form a perfect package. Toss the chickens generously with olive oil and salt. Arrange the chicken on a sheet tray or a baking dish lined with parchment or a silicone mat. Roast the chickens until they are about three-quarters of the way done, 20 to 25 minutes. The skin should start to brown and crisp.
While the chickens are roasting, combine the maple syrup and cayenne in a small saucepan over medium heat. Cook until the syrup is reduced by half to three-quarters, or until the syrup is very thick and syrupy.
After the chickens have roasted for 20 to 25 minutes, brush each piece of chicken generously with the reduced syrup. Continue to roast for another 10 to 12 minutes, brushing the skin with the syrup 1 or 2 more times while cooking. The skin should start to become very dark and sticky. If the skin starts to get too dark, cover it loosely with aluminum foil. Transfer the chickens to a serving platter and let rest about 10 minutes before serving.