How to Make It
Preheat oven to 250°F. Stir together zucchini and 1/4 teaspoon of the salt in a large wire-mesh strainer set over a large bowl. Let stand until zucchini has released water, about 15 minutes. Discard liquid. Place zucchini in a kitchen towel, and squeeze to remove excess water. Add zucchini to a large dry bowl.
Add flour, Parmesan, eggs, and garlic to bowl with zucchini; stir until combined.
Heat 1 tablespoon of the olive oil in a large nonstick skillet over medium. Add 1 heaping tablespoon zucchini mixture to skillet, flattening with spoon to create a 3-inch round. Repeat to make 3 more fritters. Cook until golden brown and slightly crisp, about 2 minutes. Flip and continue cooking until browned on both sides, about 1 more minute. Transfer fritters to a large baking sheet lined with a wire rack, and keep warm in preheated oven. Working in batches, repeat with remaining oil and batter.
Sprinkle fritters with remaining 1/2 teaspoon salt, and top evenly with sour cream and chives. Serve immediately.