Combine first 3 ingredients, 3 tablespoons lime juice, and 1 cup chicken broth in food processor; process until smooth. Transfer mixture to a large bowl; whisk in remaining 2 cups chicken broth, cream, 3/4 teaspoon salt, 1/2 teaspoon black pepper, and chopped cilantro. Chill soup mixture.
Combine shrimp, remaining 1/4 teaspoon salt, 1/8 teaspoon black pepper, and oil in a small bowl. Toss with remaining 2 tablespoons lime juice. Let stand for 15 minutes.
Ladle soup into bowls, and top each with 5 shrimp halves. Garnish, if desired.