Peel cucumbers and slice vertically so that no seeds are included.
Put the slices in a colander and sprinkle with kosher salt, which will remove the moisture. Cover with a plate or something heavy. Let sit for 30 minutes. Drain well and wipe dry with a paper towel.
Dice the cucumber slices and place in a food processor along with the garlic, lemon juice, and dill. Process until well blended. If the mixture is watery, use a very fine mesh strainer to remove excess water. Put back into the food process and add the yogurt. Blend well.
Add additional salt and pepper as needed. Place in refrigerator for at least two hours before serving so flavors can blend.