Peel shrimp, and devein, if desired, reserving shells; set shrimp aside. Bring shells and 1 cup water to a boil in a skillet over medium-high heat; boil 20 minutes. Strain stock, reserving 1/2 cup; discard remaining stock and shells.
Bring 1/3 cup port wine, garlic, ginger, and vinegar to a boil in a skillet over medium-high heat; boil 5 to 7 minutes or until reduced to 2 tablespoons. Set aside.
Melt 2 tablespoons butter with 2 tablespoons oil in a large skillet over medium-high heat. Add shrimp, 1/2 teaspoon salt, and pepper; sauté 6 to 8 minutes or just until shrimp turn pink. Remove from skillet, and keep warm.
Add green onions, curry, and hot sauce to skillet; sauté over medium-high heat 1 minute. Stir in shrimp stock, remaining port wine, and white wine; cook 8 minutes or until reduced by half. Stir in cream; cook 4 minutes or until reduced by half. Stir in reserved 2 tablespoons wine reduction and remaining butter. Add shrimp; cook until heated.
Sauté spinach in remaining hot oil 1 minute; sprinkle with remaining salt. Serve with shrimp mixture and hot cooked rice.