To prepare curry paste, heat a small, heavy skillet over medium-high heat. Add first 4 ingredients to pan; cook 1 minute or until fragrant, stirring frequently. Place spice mixture in a spice or coffee grinder; process mixture until finely ground.
Place ground spices, cilantro, and next 8 ingredients (through serrano) in a food processor; process until chopped, scraping sides. With processor on, slowly pour 1/4 cup water through food chute; process until smooth.
To prepare soup, heat 1 1/2 teaspoons oil in a large Dutch oven over medium-high heat. Add curry paste to pan; sauté 3 minutes. Add 4 cups water, wine, and clam juice; bring to a boil. Reduce heat, and simmer 30 minutes; add mussels. Cover and cook over medium-high heat 5 minutes or until mussels open; discard any unopened shells. Sprinkle with 1/3 cup cilantro. Serve immediately.