Tip:To adapt a slow-cooker recipe to a conventional oven, follow these guidelines: add more liquid, to accommodate for greater evaporation; bring the dish to a boil over high heat in a Dutch oven, then cover the pot and put in a 350°F oven. Plan on the dish taking roughly half the time to cook in the oven as it would in the slow cooker.
Season the chicken all over with the cumin, paprika, 1 tsp. of salt, and the pepper, then add to the slow cooker.
Add 1 Tbs. of oil to a 10-inch, heavy sauté pan, and heat over medium-high heat. When hot, add the chorizo and sear until cooked through, breaking the meat up with tongs, about 10 minutes. Transfer to a bowl and set aside in the refrigerator. Reduce the heat to medium. If the pan is dry, add 2 Tbs. oil. Add the onions, peppers, and garlic, and sauté until softened, scraping any bits of meat from the bottom of the pan, about 5 minutes. Pour over the chicken in the slow cooker. Add 2 more Tbs. oil to the pan, and stir in the tomato paste and flour. Sauté for 1 minute until all of the flour disappears. Raise the heat to medium high, slowly pour in the beer, and boil for 2 minutes, stirring until the sauce is smooth. Add the juices, chipotle liquid, stock, the remaining 1⁄4 tsp. salt, and the sugar, and bring to a boil over high heat. Boil until the sauce has thickened a bit, about 5 minutes.
Pour the sauce over the meat, cover, and cook on low until the chicken is tender, about 4 hours (but no more than 6 hours, or the chicken will overcook). Transfer the chicken to a bowl (leave all the sauce in the slow cooker), stir in the reserved cooked chorizo, and cover to keep warm. Add the rice, olives, and saffron to the slow cooker, cover, raise the heat to high, and cook until the rice is tender, about 30 minutes.
While the rice is cooking, prepare the peas. If using fresh peas, blanch for 2 minutes in salted boiling water and drain. If using frozen peas, defrost and drain well.
When the rice is done, stir in the reserved chorizo-chicken mixture, the peas, and cilantro. Stir to warm the chorizo through, then serve.