Preheat oven to 300 degrees F (150 degrees C). Line a baking sheet with parchment paper.
In a large bowl, stir together 3 tablespoons of sugar, the cumin, cinnamon, ginger, and cayenne pepper, and set aside.
Place the pumpkin seeds on the prepared baking sheet, spray them with cooking spray, and sprinkle with salt to taste. Bake the seeds in the preheated oven until lightly golden, 20 to 25 minutes.
Heat the oil in a large nonstick skillet over medium heat, and stir in the toasted pumpkin seeds along with 2 tablespoons of sugar. Cook and stir the seeds until the sugar forms a coating on the seeds, 2 to 3 minutes. Stir the caramelized seeds into the bowl of sugar-spice mixture, toss to coat, and let cool.