Preheat oven to 325°. Put pumpkin seeds and hazelnuts on a rimmed baking sheet (keep separate) and bake until lightly toasted, about 8 to 10 minutes. Keep oven on.
Meanwhile, toast fennel seeds in a small frying pan over medium heat until aromatic and lightly toasted, 5 to 6 minutes. Transfer to a mortar and pestle or a clean coffee grinder and coarsely grind.
Scoop up warm hazelnuts, put in a kitchen towel, and rub nuts vigorously against one another to rub off skins. Transfer to a cutting board and coarsely chop.
In a small saucepan, combine honey, sugar, and 1 tbsp. water. Bring to a simmer, stirring to dissolve sugar, then remove from heat and stir in rolled oats, fennel, and salt. Stir in pumpkin seeds, hazelnuts, and oil and mix well to combine.
Transfer granola to a rimmed baking sheet and bake until golden brown, 12 to 15 minutes. Let cool completely, then transfer to an airtight container.
Make ahead: Up to one week, stored airtight at room temperature.