Magnetic reconnection is a fundamental physical process in many laboratory, space, and astrophysical plasma contexts. Solar flares serve as an outstanding laboratory to study the magnetic reconnection and the associated energy release and conversion processes under plasma conditions difficult to reproduce in the laboratory, and with considerable spatiotemporal details not possible elsewhere in astrophysics. Here we emphasize the unique power of remote-sensing observations of solar flares at radio wavelengths. In particular, we discuss the transformative technique of broadband radio dynamic imaging spectroscopy in making significant contributions to addressing several outstanding challenges in magnetic reconnection, including the capability of pinpointing magnetic reconnection sites, measuring the time-evolving reconnecting magnetic fields, and deriving the spatially and temporally resolved distribution function of flare-accelerated electrons.