Heat the olive oil in a small skillet. Add the scallions and garlic and cook over high heat, stirring, until softened, 1 to 2 minutes. Add the curry powder and cook, stirring, for 1 minute. Scrape into a medium bowl and let cool slightly. Stir in the shrimp, cucumber and drained yogurt, and season with salt and pepper. Sprinkle the sunflower seeds over the salad and serve.