Preheat 3/4-inch oil in a large frying pan or saute pan to 360° F.
To make the dipping sauce, whisk all the ingredients in a bowl. Refrigerate until ready to use.
Place 1/2 cup flour in a shallow bowl. Add the remaining flour, cornstarch, salt, black pepper, onion powder, garlic powder, and paprika in a second shallow bowl. Whisk to blend. Next, add seltzer water until the mixture is smooth.
Place a handful of green beans in the plain flour, then move them around to coat with the flour.
Next, drop the green beans into the wet batter. Submerge them to apply an even coating.
