In the bowl of a food processor, combine red onion, parsley, garlic, and oregano until finely minced. Add chickpeas, oats, flour, feta, and sun dried tomatoes until mixture starts to come together into a large ball.
Using ¼ cup of the chickpea mixture, form patties about ½ inch thick and arrange on a parchment lined sheet pan; it will yield 6 patties.
Line a baking sheet with paper towels. Heat oil in a large skillet over medium heat. Add patties in batches and cook until golden brown, 4-5 minutes per side. You may need to add additional oil between batches. Transfer to prepared baking sheet. Assemble burgers and serve immediately.
Video
Notes
Storage: Store any leftovers in an airtight container for up to 4 days.
Freezing: Freeze uncooked patties for up to 3 months. Thaw fully before cooking.