Making the large datasets collected at the LHC accessible to the public is a considerable challenge given the complexity and volume of data. Yet to harness the full scientific potential of the facility, it is essential to enable meaningful access to the data by the broadest physics community possible. Here we present a tool, the LHCb NTuple Wizard, which leverages the existing computing infrastructure available to the LHCb collaboration in order to enable third-party users to request derived data samples in the same format used in LHCb physics analysis. An intuitive web interface allows for the discovery of accessible datasets and guides the user through the process of specifying a request for producing NTuples: an ordered set of particle or decay candidates cataloging measured quantities chosen by the user. Issues of computer security and access control arising from offering this service are addressed within its design, while still offering datasets suitable for scientific research through the CERN Open Data Portal.