In a large skillet or paella pan, heat the olive oil over medium heat. Add the onion and garlic, cooking until softened, about 3-4 minutes.
Stir in the red and green bell peppers, cooking for another 3 minutes until they begin to soften.
Add the smoked paprika and saffron, stirring to combine. Cook for 1 minute to release the flavors.
Add the Arborio rice and diced tomatoes, stirring to coat the rice with the oil and vegetables.
Pour in the chicken broth, bringing the mixture to a boil. Reduce the heat to low, cover, and simmer for 15 minutes.
After 15 minutes, add the shrimp and mussels, gently stirring them into the rice. Cover and cook for an additional 5-7 minutes, or until the shrimp are pink and the mussels have opened. Discard any mussels that do not open.
Stir in the frozen peas and season with salt and pepper to taste. Cover and let sit for 5 minutes before serving.
Garnish with fresh parsley and serve with lemon wedges on the side.