Heat the olive oil in a large, deep skillet or paella pan over medium heat.

Add the chopped onion and red bell pepper, sautéing for about 5-7 minutes until the vegetables are softened and the onion is translucent.

Stir in the minced garlic, smoked paprika, and saffron threads, cooking for another minute until fragrant to release the spice oils.

Add the tomato puree and the rice, stirring constantly for 2 minutes to coat the grains and lightly toast them.

Pour in the hot seafood stock and salt, giving it one final stir to distribute the rice evenly; bring the mixture to a gentle boil.

Reduce the heat to low and simmer uncovered for about 15 minutes, without stirring, until most of the liquid has been absorbed but the rice is still slightly al dente.

Arrange the shrimp, calamari rings, and frozen peas on top of the rice, nesting them slightly into the grains.

Cover the pan with a lid or foil and cook for another 5-8 minutes until the shrimp are pink and the calamari is tender.

Remove the pan from the heat and let it rest, covered, for 5 minutes to allow the flavors to meld and the rice to finish steaming.

Serve the Spanish seafood rice warm directly from the pan, garnished with fresh lemon wedges for squeezing over the dish.