In a wide, deep ovenproof skillet or Dutch oven on medium-high, heat 1 tsp oil. Working in batches if needed, add beef and sear until browned on all sides, turning occasionally, 6 to 8 minutes.Meanwhile, prepare a spice bag: Cut a 6-inch square of cheesecloth (double thickness), and in center of square, place anise, bay leaves, tangerine peels, arbol chiles, peppercorns, cinnamon, cardamom, fennel, coriander and cumin. Bring edges together and tie tightly with butcher’s twine.To skillet with beef, add spice bag, yellow onion, garlic, ginger, vinegar, 2 tbsp soy sauce, cane juice and 2 cups water. Increase heat to high and bring to a boil. Reduce heat to medium-low, cover and simmer, stirring occasionally and adjusting heat if necessary so that liquid is bubbling gently, until beef is tender enough to pull apart when pierced with a fork, about 1 hour, 30 minutes.Strain beef and onions through a fine mesh sieve over a bowl to reserve broth, then discard spice bag and return broth to pan. Bring to a boil and reduce broth by half, about 5 minutes. Meanwhile, in a large nonstick skillet on medium-high, heat remaining 1 tsp coconut oil on medium high. Add cubanelle and jalapeño peppers and sauté until softened, about 2 minutes. Stir in beef and onion mixture, green onions, broth and remaining 1 tbsp soy sauce and cook, stirring and breaking up beef slightly, about 2 minutes. Set aside.Heat a large nonstick skillet on medium. Working in batches if needed, mist buns or muffins with cooking spray and toast in skillet until crisp and brown on the outside and steaming on the inside. Open buns carefully, leaving 1 side attached. Divide beef and cilantro among buns, pouring any excess broth into buns.