Heat the olive oil in a large, wide skillet over medium heat. Add the chopped onion and red bell pepper, sautéing until softened and translucent, which should take about 5 to 7 minutes.

Stir in the minced garlic, smoked paprika, and crushed saffron threads. Cook for about 1 minute until highly fragrant, stirring constantly to ensure the garlic doesn't burn.

Pour in the crushed tomatoes and the short-grain rice, stirring well to coat the grains in the tomato and spice mixture. Let it cook for 2 minutes to lightly toast the rice before adding the liquid.

Pour in the broth, season with salt and black pepper, and stir gently to distribute everything evenly across the pan. Bring the liquid to a gentle simmer, then reduce the heat to medium-low and let it cook uncovered for 15 minutes without stirring.

Nestle the shrimp and mussels gently into the simmering rice and scatter the frozen peas evenly over the top. Cover the skillet loosely with a lid or foil and cook for another 8 to 10 minutes, or until the shrimp are opaque and the mussels have fully opened.

Remove the skillet from the heat and carefully discard any mussels that remained closed during cooking. Let the dish rest for 5 minutes to absorb any remaining liquid, then serve warm directly from the pan with fresh lemon wedges on the side.