Make the stock: Combine the chicken wings, onion, celery, carrot, bay leaves, thyme, peppercorns and juniper berries in a large pot and add water to cover. Bring to a simmer over medium low to medium heat; simmer, uncovered, 45 minutes. Add the saffron and simmer 15 more minutes. Strain the stock: Pour the stock through a fine strainer; discard the solids. (If not using immediately, let cool, then cover and refrigerate up to 3 days or freeze up to 3 months.)
Poach the chicken: Bring 8 cups water, the quartered onion, bay leaf and celery to a simmer in a large pot over medium heat. Add the chicken thighs and gently poach until just tender, about 12 minutes.
Shred the meat: Remove the chicken from the pot using tongs and reserve the poaching liquid. Let the chicken cool slightly, then discard the skin and shred the meat. Make the sauce: the tomato paste, ketchup and paprika in a blender. Strain 2 cups of the reserved poaching liquid; add the liquid to the blender and puree until smooth.
Finish the chicken: Heat the vegetable oil in a large skillet over medium heat. Add the sliced onion, bell peppers and garlic and cook until translucent, 10 to 12 minutes. Add the pureed sauce and cook, stirring, until the sauce thickens, 8 to 10 minutes. Add the shredded chicken and stir to coat with the sauce. Season with salt and keep warm.
Make the paella: Preheat the oven to 350 degrees F. Heat the olive oil in a paella pan or large ovenproof skillet over medium-high heat. Add the chorizo and cook until the fat renders, about 5 minutes. Add the onion and garlic and cook until the onion is translucent, about 10 minutes. Add the rice and stir to lightly coat with the oil. Stir in the peas, piquillo peppers, olives, 2 cups chicken mixture and 2 1/4 cups saffron chicken stock. Season with salt. Bake and serve: Cover the paella pan or skillet tightly with foil and bake until the liquid is completely absorbed, 20 to 22 minutes. Remove from the oven and let rest, covered, 5 minutes. Serve in the pan. Photograph by Andrew Sabin
Recipe courtesy Jose Garces for Food Network Magazine