Peel and slice the sweet onion into half-inch thick rings, carefully separating the layers.
In a medium bowl, whisk together the chickpea flour, garlic powder, smoked paprika, sea salt, and black pepper until well combined.
Slowly pour the light beer and egg whites into the dry ingredients, whisking until a smooth and thick batter forms.
Lightly coat the air fryer basket with the avocado oil spray and preheat the unit to 375 degrees Fahrenheit.
Dip each onion ring into the batter, allowing any excess to drip off, and place them in a single layer in the air fryer basket.
Air fry for 8 to 10 minutes, flipping halfway through, until the coating is golden brown and crisp.
While the rings are cooking, stir together the Greek yogurt, sriracha, and lemon juice in a small bowl to create the zesty dipping sauce.
Serve the hot onion rings immediately alongside the chilled dipping sauce for a high-protein meal with a perfect crunch.