The presence of fine crystals is a common condition that may hinder the downstream processing of a powder obtained through a crystallization process. This study investigates through simulations a process featuring a hydrocyclone for their removal. Hydrocyclones, solid-liquid separation devices widely applied in several fields of chemical engineering, enable the classification of suspended solids based on their size. The classification step allows for a selective dissolution of the fine crystals, thus leading to a more efficient process when compared to a simpler temperature cycle, where partial dissolution of larger crystals is deliberately though reluctantly accepted. A pathway for the selection of a suitable hydrocyclone design is outlined, and a novel graphical tool useful to describe the performance of the device for the fines separation task is presented. The selection of the operating variables and their operating window is discussed, and their effect on the overall process is elucidated. The design space and the performance of the selective fines removal process is investigated by coupling for the first time the detailed modeling of fines dissolution by heating and crystallization by cooling, both based on population balance equations, and the hydrocyclone behavior, for which an established model due to Braun is used. Simulation runs are presented for different scenarios and allow assessing the process performance in terms of reductions of fines, processing time, and energy demand, thus providing a valuable insight into its applicability.