Stir Greek seasoning and water together in a small bowl; let stand until seasoning is moistened, about 5 minutes.
Crush the garlic clove with the side of a knife; sprinkle kosher salt over garlic and mash garlic and salt together into a paste with the edge of the knife.
Whisk garlic mixture, olive oil, wine vinegar, lemon juice, lemon zest, Dijon mustard, pepper, and sugar into Greek seasoning mixture until combined.