Trim and coarsely shred zucchini (you should have about 5 cups). In a large bowl toss zucchini with salt. Place in a colander or sieve. Place a plate or 9-inch pie plate on top of zucchini and weight down with cans or another bowl. Let drain in the sink or over a bowl for 15 minutes. Discard liquid.
In the large mixing bowl, beat eggs and garlic. Stir in flour, Parmesan cheese, onion, and pepper until just moistened (batter should be lumpy). Stir in shredded zucchini until just combined (mixture will be thick).
For each zucchini pancake, spoon a rounded tablespoon of batter onto a hot, lightly oiled griddle or heavy skillet, spreading to form a 3-inch circle. Cook over medium heat for 2 to 3 minutes on each side or until the pancake is golden brown. (Reduce heat to medium-low if pancakes brown too quickly.) Keep pancakes warm in a 300 degree F oven while cooking remaining pancakes.
Serve warm topped with a dollop of sour cream, if desired. Or cool, place in layers in a freezer container with waxed paper between layers.
To reheat; preheat oven to 425 degrees F. Place frozen pancakes in a single layer on a greased or parchment-lined baking sheet. Bake, uncovered, for 8 to 10 minutes or until hot and slightly crisp. Makes about 30 pancakes.