Bring broth to a boil in a medium saucepan. Add shrimp to soup and bring back to a boil. Add spinach and bring back to a simmer.
Pour beaten eggs into soup in a steady stream; eggs will curdle into ribbon shaped strands. Season to taste with salt and pepper and remove saucepan from heat. Immediately ladle into soup bowls and drizzle a few drops of sesame or chili oil or chili paste into your soup. Add drops of lime juice if you wish.