Using the large holes of a box grater, grate 3 carrots and transfer to a large serving bowl. Grate 2 cucumbers over a kitchen towel or paper towels.
Spread the grated cucumbers into an even layer; sprinkle with ¼ teaspoon salt. Let stand until water starts to leach out, about 5 minutes. Gather the edges of the towel or paper towels around the cucumber; squeeze over the sink to remove excess water. Transfer to the bowl with the carrots.
Whisk ½ cup yogurt, 1 tablespoon each vinegar, herbs and mayonnaise, 1½ teaspoons honey, 1 teaspoon lemon juice, ½ teaspoon each garlic powder and pepper and the remaining ¼ teaspoon plus ⅛ teaspoon salt together in a small bowl until smooth. Add to the carrot mixture and toss until evenly coated. Garnish with additional herbs, if desired.
