Remove the stems and the seeds from the dried chiles, if using. Rinse and place in a saucepan with water to cover. Bring to a boil, then remove from the heat, cover and let stand for 1 hour. Drain and set aside. Preheat the oven to 350 degrees. In a blender or food processor, puree the softened chiles or chile powder with the wine, orange juice, vinegar, garlic, fresh chiles, ground spices, oregano and salt until smooth. Scatter half of the onions and raisins in a roasting pan and place the beef on top of them. Scatter the remaining onions and raisins over the beef and then pour on the chile mixture, spreading with a spatula to evenly coat the meat. Cover the roasting pan tightly and bake until the brisket is very tender, about 4 hours. Shred the meat with a fork and mix with the onions and juices. Serve on warmed tortillas garnished with cilantro, a squeeze of lime, sliced avocados, queso fresco or crumbled fresh feta cheese.