To be honest with you, we haven’t ever fried a radish or seen a recipe for one. But it sounds intriguing.
There are many varieties of radish, and single varieties range in color from black to purple to brown to red to pink and to white. So your request for us to pull a white radish out of our hats isn’t as simple as it sounds. We think what you’re probably looking for, though, is the daikon or mooli - the only radish variety that sees much use in cooking. Daikon, which is long and slender, is sometimes sliced and added to stir-fry dishes in Asia. And it is readily available in this country.
Radishes are the roots of plants in the mustard family, which accounts for their pungency and peppery taste (and, of course, their cousin is the horseradish). The radish that most of us think of in the US, called simply radish or small radish (red, white, or mixed), is only the tip of the radish iceberg. Not only do they come in various colors, the same variety of radish can also range in shape from round to spindle-shaped and from cylindrical to oval. Within a particular variety, though, neither the color or shape has much bearing on its taste.
Not having fried a single radish in our lives, we can’t give much advice. But from the depths of our French fry wisdom, we know that you choose a russet or other baking potato for frying because it is drier than other varieties. So, because radishes are watery, we would suggest blotting the daikon before dropping it in the oil. Also with French fries, you fry them twice - once at 350°F (175°C) to cook the inside until it is fluffy, and subsequently at 385°F (195°C) to brown the outside. Whether those results are desirable and/or obtainable in a fried radish, we couldn’t say. Let us know how it turns out….