  A fundamental goal of modern-day astrophysics is to understand the connection
between supermassive black hole (SMBH) growth and galaxy evolution. Merging
galaxies offer one of the most dramatic channels for galaxy evolution known,
capable of driving inflows of gas into galactic nuclei, potentially fueling
both star formation and central SMBH activity. Dual active galactic nuclei
(dual AGNs) in late-stage mergers with nuclear pair separations $<10$ kpc are
thus ideal candidates to study SMBH growth along the merger sequence since they
coincide with the most transformative period for galaxies. However, dual AGNs
can be extremely difficult to confirm and study. Hard X-ray ($>10$ keV) studies
offer a relatively contamination-free tool for probing the dense obscuring
environments predicted to surround the majority of dual AGN in late-stage
mergers. To date, only a handful of the brightest and closest systems have been
studied at these energies due to the demanding instrumental requirements
involved. We demonstrate the unique capabilities of HEX-P to spatially resolve
the soft and - for the first time - hard X-ray counterparts of
closely-separated ($\sim2''-5''$) dual AGNs in the local Universe. By
incorporating state-of-the-art physical torus models, we reproduce realistic
broadband X-ray spectra expected for deeply embedded accreting SMBHs. Hard
X-ray spatially resolved observations of dual AGNs - accessible only to HEX-P -
will hence transform our understanding of dual AGN in the nearby Universe.
