In a pot or deep fryer, heat oil to 375°F.
Try to maintain this temperature throughout cooking to keep the fried beans light and crispy.
In a large bowl, whisk together cornstarch, flour, baking powder, salt, sparkling water, oil and, if desired chile flakes.
Sprinkle more cornstarch on a plate.
Lightly coat each green bean in cornstarch and shake off excess.
Dip into batter and slide into hot oil, letting cook 3 to 4 minutes until crisp and golden brown.
Let drain on a paper towel covered plate.
*Zucchini, mushrooms and pea pods can also be used.*
**Tempura is best eaten freshly made and warm, but if stored over night in the fridge, a quick blast under the broiler on a baking sheet can reheat the beans while maintaining some crunch.**