Preheat oven to 375°F. Coat baking sheet with cooking spray. Heat oil in small skillet over medium-low heat. Add onion, and cook 10 minutes, or until light brown, stirring occasionally. Add garlic and chopped sage, and cook 2 minutes more. Transfer to bowl.Combine pumpkin purée, breadcrumbs, egg, salt, and pepper in bowl with onion mixture. Form into 1 1/2 -inch balls, and transfer to prepared baking sheet. Bake 10 to 15 minutes, or until bottoms are golden brown.Pour enough oil in large skillet to coat bottom 1/8 inch. Heat over medium heat until oil shimmers. Add sage leaves in single layer, and fry 20 to 30 seconds, or until brittle but still bright green. Transfer to paper-towel-lined plate, and sprinkle with salt. Serve pumpkin balls with sage leaves and green pepper sauce.