3 cups pineapple juice 1/2 cup white wine vinegar 1 tablespoon fresh ginger, finely chopped 3 tablespoons soy sauce 1/4 cup light brown sugar, firmly packed 2 tablespoons Dijon mustard 3 tablespoons lime juice 1 teaspoon freshly ground white pepper 2 pounds fresh tuna steaks, finely chopped 2 tablespoons Dijon mustard 2 teaspoons chipotle pepper puree 1 tablespoon honey 2 tablespoons canola oil 2 green onions, thinly sliced Salt and freshly ground pepper 8 rolls or hamburger buns
Combine the pineapple juice, vinegar, ginger, soy sauce and brown sugar in a small saucepan and bring to a boil. Reduce the heat to low and simmer until the volume is reduced by half, about 30 minutes. Whisk in 2 tablespoons mustard, remove from the heat, and add the lime juice and white pepper. Let cool.
Combine the tuna, 2 tablespoons Dijon, chipotle pepper puree, honey, oil, and green onions in a large bowl, and season with salt and pepper. Shape the ground tuna firmly into 8 round uniform patties about 1 1/2-inches thick. Refrigerate for 30 minutes; the burgers must be very cold to hold their shape when cooking. Grill burgers for 3 minutes on each side for medium doneness, basting often with the glaze. Serve the burgers on rolls or buns.