Toast the saffron threads, until fragrant and a shade darker. When cool, crumble with your fingers. Sprinkle the chicken generously with salt and pepper. Warm 1 Tbs olive oil over medium heat. Add chorizo slices and brown.
Transfer the chorizo to a plate to drain. Pour off all but 2 Tbs of fat from the pan.
Return the pan to medium heat. Working in batches, add the chicken and cook, turning as needed, until nicely browned on all sides, about 5 minutes. Transfer to a plate.
Add the onion and garlic to the pan and sauté until soft and translucent. Add the tomatoes and cook, stirring, until most of the liquid has evaporated, 3-5 minutes. Add wine, stock, paprika, and saffron and season to taste with salt and pepper. Bring to a boil.
Sprinkle the rice evenly over the bottom of pan, arrange the chicken and chorizo over the rice, submerging them in broth. Bring to a boil over high heat and cook for 10 minutes.
Arrange the clams, mussels, and shrimp over the rice. Push the seafood down into the liquid. Reduce the heat to low and simmer until the clams and mussels have opened, the shrimp are pink, and the liquid is absorbed, 10-12 minutes. Using a wooden spoon, push aside the rice to see if there is a brown crust on the bottom. If one hasn’t formed yet adjusting the heat as necessary to brown, but not burn, the rice.
Remove from heat. Arrange the pepper strips and peas over the rice, cover with aluminum foil, and let stand for 10 minutes. Serve at once directly from the pan, with lemon wedges on the side or spread throughout the Paella.