Bring a medium-size pot of water to boil. Peel the kohlrabi bulbs and boil whole until a fork can pierce through to the center with minimal resistance.
While the kohlrabi is boiling, blend together the yogurt, cilantro, mustard, and red pepper flakes in a blender or food processor, or with an immersion blender. Season with salt to taste. Scoop into small ramekins for dipping.
Let the bulbs cool, then slice into 1/2- to 3/4-inch thick strips.
Heat the oil in a skillet on the stove over medium-high heat. Dredge the kohlrabi slices in flour that has been seasoned with a dash of salt and papper, egg, and breadcrumbs. Then fry until brown and crispy, about 2 minutes on each side.
Let cool on a paper towel drain off any excess oil. Serve with the dipping sauce on the side.