Peel the sweet onion and slice it into 1/2-inch thick rings, separating them carefully.
Peel and devein the shrimp, then pat them completely dry with a paper towel to ensure the batter adheres.
In a medium-sized bowl, whisk together the cassava flour, garlic powder, smoked paprika, sea salt, and black pepper.
Add the light beer and egg white to the dry ingredients, whisking until a smooth, thick batter forms.
Prepare the zesty dip by combining the Greek yogurt and sriracha in a small bowl; stir well and set aside in the refrigerator.
Dip each onion ring and shrimp into the beer batter one by one, allowing any excess to drip off.
Lightly coat the air fryer basket with avocado oil and arrange the battered items in a single layer without overcrowding.
Air fry at 375°F for 10 to 12 minutes, flipping halfway through, until the coating is golden-brown and crispy.
Serve the hot onion rings and shrimp immediately alongside the chilled zesty yogurt dip.