In a large nonstick skillet, heat 2 tablespoons oil over medium-high. Add potatoes, and cook, stirring occasionally, until browned and crisp, 12 to 14 minutes. Add scallion whites, and cook 1 minute more. Transfer to a plate (reserve skillet).
Add remaining teaspoon oil, shrimp, and curry powder to skillet; cook, stirring occasionally, until shrimp are cooked through, 2 to 3 minutes. Return potatoes and scallion whites to skillet, and toss with shrimp; season with salt and pepper. Serve topped with scallion greens.