Combine garlic and 1 teaspoon salt in small bowl. Mix in yogurt. (Can be prepared 3 hours ahead. Cover and refrigerate.)
Pour oil into heavy medium saucepan to depth of 1 1/2 inches and heat to 350°F
Place 1 1/2 cups flour in medium bowl. Whisk in enough water to form smooth medium-thin batter. Place remaining 1 cup flour in large bowl. Working in batches, add zucchini to flour in bowl and toss, separating slices to coat well. Dip zucchini into batter and fry until golden, about 3 minutes per side. Transfer to paper towels and drain.
Place yogurt in center of large platter. Surround with zucchini and serve.