Preheat oven to 250 degrees. Line a baking sheet with parchment paper. Cut pumpkin open from the bottom, removing seeds with a long-handled spoon. Separate flesh from seeds, and reserve the flesh for another use (see Pumpkin Pie). Pumpkin should yield 1 cup seeds. Spread seeds on parchment in an even layer. Bake until dry, stirring occasionally, about 1 hour. Let cool.
In a medium bowl combine 3 tablespoons sugar, salt, cumin, cinnamon, ginger, and cayenne. Heat peanut oil in a large nonstick skillet over high heat. Add pumpkin seeds and remaining 2 tablespoons sugar. Cook until sugar melts and pumpkin seeds begin to caramelize, about 45 to 60 seconds. Transfer to bowl with spices, and stir well to coat. Let cool. These may be stored in an airtight container for up to 1 week.