Mix together the soy sauce, ginger, sugar, garlic, jalapenos and cilantro in a large container. Submerge the ducks in the marinade and marinate in the refrigerator for 72 hours.
Preheat charcoal embers in a gas grill, or prepare an electric grill for indirect/low heat. Remove the ducks from the marinade and spear with metal churrasco swords or large metal skewers. Cook over embers, turning frequently, for 4 hours.
NotesThis recipe was provided by a chef, restaurant or culinary professional and makes a large quantity. The Food Network Kitchens have not tested it for home use and therefore cannot make any representation as to the results.