Devein shrimp with small kitchen scissors, but do not peel. Pat dry.
Combine curry powder and next 3 ingredients in a small bowl; set aside.
Heat 1 tablespoon oil in a large heavy skillet. Sear half of shrimp on both sides until shells turn crisp and orange.
Remove from pan, and set aside. Repeat with 1 tablespoon oil and remaining shrimp.
Heat remaining 1 tablespoon oil in skillet over medium-high heat. Saut garlic and green onions 30 seconds. Stir in reserved curry powder mixture, and saut 1 minute or until fragrant.
Add shrimp, butter, lemon juice, and cilantro. Cook, stirring constantly, until butter melts and seasoning coats shrimp.