In a large food processor, add all ingredients except oats and using 2 3/4 cups of pumpkin seeds (and reserving the remaining 1/4 cup). Puree until well combined, scraping down the bowl as needed.
Add oats and pulse through several times to incorporate.
Add the reserved 1/4 cup of pumpkin seeds, and pulse in again, just to slightly incorporate but keep some texture.
If possible, refrigerate for about an hour.
When ready to bake, preheat oven to 375°F. Take scoops of mixture (about 1–1 tbsp; should yield 54-60 meatballs), and place on 2-3 baking sheets lined with parchment paper.
Bake for 18–20 minutes, until golden or just firm to the touch (do not over-bake, they will dry out).
Remove and serve with pasta and tomato sauce, or with rice and sauce of choice.