Peel the garlic and press it through a garlic press. Wash and grate the cucumber. Mix garlic, cucumber, yoghurt and sour cream. Season with salt and pepper. Cover and chill for about 30 minutes. In the meantime wash and clean the radishes and cut them into wafer-thin slices.
Wash and drain the corn. Wash the dill and cut finely, except for a few flags for garnishing. Stir the radishes, corn, dill and crab meat into the cold dish. Season to taste again. Serve garnished with dill flags