Heat oil in a large, heavy saucepan set over medium heat. When hot, add onion, carrot, and celery and sauté until softened—3 to 4 minutes. Add rice, saffron, wine and stock and bring to a simmer. Season with 1 teaspoon salt. Bring mixture to a simmer, then reduce heat. Cover and cook at a simmer until vegetables and rice are soft, for about 20 minutes. Remove from heat and let cool for 10 minutes. Puree the soup in batches in a food processor or blender and return it to the pot. Stir in the cream. Set soup over low heat and, when mixture comes to a simmer, add shrimp, chorizo, peas, and, if desired, chicken. Cook until shrimp have turned pink and curled, for about 3 minutes. Do not overcook or shrimp will become tough. Taste soup and season with salt, as needed. Garnish with a sprinkle of chives.