Clean Shrimp and pat dry. Drizzle mixture of lemon and line juice over shrimp. Sprinkle chili powder over shrimp. Arrange shrimp in the shallow baking pan. Roast in oven until cooked through. Discard stems from spinach and sliced green onions. In a large skillet over medium heat, bring water with gingerroot to a simmer. Add spinach; cook while stirring until slightly wilted, about 20 seconds. Remove skillet from heat and stir in green onions and oil. Season with salt and pepper. Serve shrimp over spinach.