Bring a small pot of water to a simmer. Add the garlic cloves and cook until tender, about 20 minutes. Drain, then let cool slightly; slip off the skins.
In a small bowl, combine the sour cream, horseradish and crushed red pepper.
Fill a medium pot with enough oil to reach a depth of 2 inches and heat over medium-high heat until it registers 365 degrees on a deep-fry thermometer. Meanwhile, in a medium bowl, whisk together the flour, baking soda and 1 teaspoon salt. Whisk in the ice water to form a smooth batter.
Working in batches of no more than 8 pieces, coat the radish slices with the batter. Drop them one at a time into the oil, gently stirring to prevent sticking. Fry until golden and crisp, 1 to 2 minutes; transfer to paper towels to drain. Repeat with the garlic cloves and jalapenos. Sprinkle with salt and serve with the horseradish dip.