The long-range character of the Rydberg-Rydberg interaction leads to strong boundary effects especially in small low-dimensional systems. Thus, control of the initial density distribution is crucial for the coherent manipulation of such many-body systems. Based on the preparation of uniform atomic density distributions with sub-shotnoise atom number fluctuations, we succeeded to realize crystalline states by adiabatic ramping techniques. Furthermore, we report on the coherent manipulation of a single superatom whose "size" is tunable between one and a hundred atoms.