In a small bowl, soak the saffron threads in 2 tablespoons of warm seafood stock and set aside.
Heat olive oil in a large paella pan or wide skillet over medium heat.
Add the chopped onion and diced red bell pepper, sauté for 5 minutes until softened.
Add the minced garlic and cook for 1 minute until fragrant.
Stir in the rice, smoked paprika, and grated tomato; cook for 2 minutes, stirring frequently to coat the rice with the oil and spices.
Pour in the white wine and let it simmer until mostly absorbed, about 2 minutes.
Add the seafood stock and the saffron with its soaking liquid. Stir to combine and bring to a gentle boil.
Reduce heat to medium-low and cook uncovered without stirring for 15 minutes.
Arrange the shrimp, mussels, squid rings, and clams evenly over the rice. Sprinkle the peas on top.
Continue cooking for another 15 minutes until the seafood is cooked through, the rice is tender, and most of the liquid is absorbed. If the rice needs more cooking and liquid is absorbed, add a little hot seafood stock as needed.
Season with salt and freshly ground black pepper to taste.
Remove the pan from heat, cover with a clean kitchen towel, and let rest for 5 minutes.
Garnish with chopped fresh parsley and lemon wedges before serving.