Line a baking sheet with a few layers of paper towel. Lay the zucchini noodles down and sprinkle with salt. Top with another few layers of paper towel, a cutting board and some heavy items like books or pots. Let sit for 10 minutes.
After 10 minutes, transfer the noodles to a colander and rinse thoroughly with cold water to remove the salt.
Refresh the paper towels on the baking sheet with a few new layers. Gently squeeze and shake the zoodles and lay them down on the paper towel. Top with a few more layers of paper towel, the cutting board and the heavy items. Let dry for 10 minutes.
Meanwhile, heat the oil in a large skillet over medium low heat and add the onion. Cook for about 50-60 minutes until deeply caramelized and golden brown. Add in the garlic and sage and cook for another 3 minutes.
Add in the pumpkin, ricotta, milk, parmesan, maple, cinnamon and salt and pepper, to taste. Cook over medium heat until warmed through and bubbling and the graininess of the ricotta disappears, Add in the zoodles and toss until everything is well coated and the zucchini are cooked through, about 3-5 minutes.
Divide between plates and top with additional parmesan and pumpkin seeds.