Place the shredded zucchini in a colander and sprinkle it lightly with salt. Let the zucchini sit for 10 minutes then using your hands, squeeze out as much liquid as possible.
Transfer the zucchini to a large bowl then add the carrots, garlic, flour, eggs, scallions, 1/4 teaspoon salt and 1/8 teaspoon pepper. Stir the mixture until it is combined.
Line a plate with paper towels. Place a large sauté pan over medium-high heat and add the olive oil. Once the oil is shimmering, scoop 3-tablespoon mounds of the vegetable mixture into the pan, flattening the mounds slightly and spacing them at least 1 inch apart.
Cook the fritters for 2 to 3 minutes then flip them once and continue cooking them an additional 1 to 2 minutes until they’re golden brown and crispy. Transfer the fritters to the paper towel-lined plate, season them with salt and repeat the cooking process with the remaining mixture.
Serve the fritters immediately topped with sour cream or yogurt.