Either grate the zucchini, carrots and onion by hand, or use the food processor attachment. Line a colander with a thin dish towel and add the grated veggies on top. Toss with 1/2 tsp salt and let sit for 10 mins. Then, bundle the towel and squeeze as much excess liquid out of the grated veggies as possible. Add to a large bowl.
To the bowl, add the rest of the zucchini fritter ingredients except the oil and mix well.
Heat a large cast iron or nonstick skillet over medium heat for 5 mins. Add 1/2 inch of oil and allow to heat for another minute or until a drop of water sizzles.
Scoop out 1/4 cup of the zucchini fritter batter and add to the skillet, using a fork or spatula to flatten. Repeat but don't overcrowd the pan.
Fry on each side for about 3 minutes or until golden brown. Flip and fry for another 3 minutes. Remove and place on a paper towel lined plate.
In a small bowl, whisk together the yogurt herb dipping sauce ingredients.