Clean and peel cucumbers, chopping them into chunks. If desired, English cucumbers can be substituted for common cucumbers.
Chop garlic and sweet onion into pieces. Place garlic, onions, cucumbers, and 1/2 cup of chicken stock into a food processor or blender. Blend until somewhat smooth in texture with some chunks of cucumber remaining or blend to consistency desired. Place blended ingredients in a large bowl.
Add yogurt, remaining chicken stock, lemon juice, salt, and pepper to combined ingredients in bowl and whisk all contents together until well blended. Season to taste. Add more chicken broth if necessary to achieve desired consistency.
Pour soup into a tightly covered container and place in refrigerator to chill for several hours or overnight.
Serve cold. You may choose to garnish with fresh herbs such as parsley, cilantro or basil. Sprinkle freshly grated Parmesan cheese or any other hard cheese desired, such as sharp cheddar.