Flatten and peel the garlic clove by placing it on a cutting board beneath the blade of a large knife. Give the knife a whack with your fist, being careful to avoid the sharp edge. The peel should come off easily. Chop the garlic into very small pieces. Sprinkle the salt onto the garlic, and make a paste by alternatively chopping and rocking the flat blade of the knife over the mixture.
Place garlic-salt paste in a small mixing bowl. Add the parsley, chives, mayonnaise and red wine vinegar. With a fork, stir to combine.
If necessary to make the dressing pourable, add water, 1/2 teaspoon at a time, stirring after each addition until it reaches the desired consistency.