1. For the annatto oil: Put the olive oil and annatto seeds in a small saucepan over medium heat. When the annatto seeds start to sizzle, after 2 or 3 minutes, turn off the heat and allow the oil to cool. Strain out the seeds and reserve the oil.
2. For the filling: Put the cilantro, cider vinegar, garlic, celery, onions, orange juice, bell peppers and 1/2 teaspoon salt in the bowl of a food processor and blend to a chunky paste.
3. Heat 2 tablespoons of the annatto oil in a large heavy-bottomed pan or Dutch oven over medium-high heat. Sprinkle salt and pepper on the pork. Add half of the pork to the pan and brown on all sides, 4 to 5 minutes. Remove to a bowl and repeat with the remaining pork. Set aside.
4. Add the pureed vegetables to the pan and reduce the heat to medium. Cook, stirring occasionally, until the liquid has evaporated and the vegetables start sticking to the pan, about 8 minutes. Add the tomato paste and cook, stirring constantly, 2 minutes. Add the browned pork with its juices and the chicken stock. Bring to a simmer, cover and cook until the pork is tender, about 1 hour. If the sauce is too thin, remove the lid, increase the heat to medium and cook until thickened. Season with salt and pepper. Set aside to cool completely.
5. For the dough: Add the squash, chicken stock, plantains, 3 tablespoons of the annatto oil and 2 1/2 teaspoons salt to the bowl of a food processor. Blend into a smooth wet paste.
6. To make the pasteles: Bring a large pot of salted water to a simmer. Wipe the banana leaves clean and cut out fifteen 12- by 10-inch pieces; cut out the tough side ribs for easier folding. Lay out a piece of banana leaf. Spoon 1/4 cup of the dough onto the bottom half of the leaf and spread it into a 4- by 4-inch square. Put 2 tablespoons of the pork filling (side by side to make a rectangle) in the middle of the dough and place 4 olive halves on top of the filling. Take the bottom half of the banana leaf and fold it over about a third of the way up so the dough is completely encasing the filling. Continue folding like a burrito, tucking in the sides. If there are any tears in the leaf, patch them with scrap pieces of banana leaf. Tie the packet with butcher's twine, as though you were wrapping a birthday present. Repeat with the rest of the banana leaves. You should have enough filling and dough to make 15 pasteles.
7. Put the pasteles in the simmering water and cover with a lid. Simmer for 30 minutes. Remove with a slotted spoon.
8. To serve, cut off the twine and carefully unwrap the hot pasteles. Serve with hot sauce on the side.