Preheat the air fryer to 400 degrees F (200 degrees C) and the oven to 200 degrees F (95 degrees C).
Combine flour, 1/4 teaspoon salt, and pepper in a shallow dish. Whisk eggs and water together in another shallow dish. Stir panko and oil together in a third shallow dish.
Sprinkle green beans, asparagus, red onion, sweet pepper, avocado, and zucchini with remaining 1/4 teaspoon salt; dip in flour mixture, then in egg mixture, and finally in panko mixture to coat.
Arrange half of the vegetables in a single layer in the air fryer basket. Cook until golden brown, about 8 to 10 minutes. Sprinkle with additional salt, if desired. Transfer vegetables to oven to keep warm. Repeat with remaining vegetables.