Mix club soda, rice flour and salt. Whisk to get the lumps out. Dip sliced vegetables in batter, removing the excess batter.
Heat oil in a deep pot or skillet. It should be two or three inches deep. Oil is ready when it reaches 350°F, or when a pinch of batter sizzles. If the oil isn't hot enough, the vegetables will soak up the oil.
Fry the vegetables, a few at a time to keep the oil hot, turning with a slotted spoon after they look crispy. The vegetables are done when they are golden and crispy.
Place veggies on paper towels or a rack to let oil drip off. Sprinkle with salt. Serve with dipping sauce.