1 medium, ripe tomato (about 6 ounces)
12 large shrimp (about 9 ounces), peeled and deveined
3/4 teaspoon smoked Spanish paprika (pimentón dulce)
Freshly ground black pepper
8 ounces boneless, skinless chicken thighs, cut into 1-inch pieces
6 ounces Spanish chorizo, cut into 1/4-inch-thick rounds
1 to 2 tablespoons olive oil, as needed
2/3 cup small-dice yellow onion (from about 1/3 medium onion)
1 medium garlic clove, finely chopped
1 pinch saffron threads
1 1/3 cups paella rice (about 10 ounces), sometimes labeled bomba or Valencia
3/4 teaspoon kosher salt, plus more for seasoning the shrimp and chicken
2 2/3 cups low-sodium chicken broth
12 mussels, Manila clams, or a combination, scrubbed
1 tablespoon coarsely chopped fresh Italian parsley leaves
1 medium lemon, cut into 8 wedges, for serving