01 - Preheat the air fryer to 400 degrees Fahrenheit.
02 - Separate the onion slices into rings and reserve the small inner pieces for another use.
03 - Arrange three shallow bowls: Combine flour, salt, and black pepper in the first; whisk eggs and buttermilk in the second; mix panko breadcrumbs with smoked paprika in the third.
04 - Dredge each onion ring in the seasoned flour mixture, shaking off any excess.
05 - Dip the floured rings into the egg and buttermilk mixture, ensuring full coverage.
06 - Press each ring into the panko breadcrumb mixture until thoroughly coated.
07 - Place the breaded onion rings in a single layer in the air fryer basket and lightly spray with olive oil.
08 - Cook for 10 to 12 minutes, flipping halfway through and spraying again with olive oil, until golden brown and crispy.
09 - Combine all burger sauce ingredients in a small bowl, adjusting seasoning to taste.
10 - Serve the hot onion rings alongside the burger sauce.