In a large skillet, heat the vegetable oil to 375°. Pat the tomatillo slices dry with paper towels. One at a time, dip the tomatillo slices in the batter. Using tongs, add the slices to the oil in a single layer, without crowding the skillet. Fry the tomatillo fritters, turning once, until golden, 1 to 3 minutes total. Drain the fritters on paper towels and keep warm in a low oven. Season with kosher salt and serve as soon as possible.