Position a rack in the center of the oven and heat the oven to 350°F.
Rinse the capers well. If using salt-packed capers, soak them in warm water for at least 5 minutes. (They should taste capery rather than salty; if not, continue soaking for a little longer.) Drain the capers and, unless they’re very small, coarsely chop them. Combine the capers, cabbage, red onion, parsley, chives, oregano, and chiles (if using). Add the vinegar and 1/4 tsp. salt, toss well, and let sit at room temperature for at least 30 minutes. Toss again and season to taste with more salt or chile.
Meanwhile, put the pork in a small baking dish. (If you have any juices left, scrape them into the dish, skimming and discarding as much of the congealed fat as possible.) Cover with foil and bake the pork until warmed through, 10 to 15 minutes. Remove the pork from the oven, position a rack 6 inches from the broiler, and heat the broiler to high.
Cut the baguette crosswise into 4 equal portions (each 5 to 6 inches long) and then slice each piece horizontally so that it opens like a book. Just before serving, put the baguette pieces on a baking sheet, opening each as much as possible, and toast very lightly under the broiler, 2 to 3 minutes. Divide the pork into 4 equal portions and mound on the bottom half of each piece of baguette. Drizzle any pan juices over the pork and then pile on the cabbage slaw. Drizzle the olive oil over the slaw. If any vinegar has collected on the bottom of the slaw bowl, distribute it among the sandwiches, and serve.
nutrition information (per serving):
20, Fat Calories
180, Saturated Fat
28, Monounsaturated Fat
12, Polyunsaturated Fat
Photo: Scott Phillips