  In this paper we develop the theory for 2D-to-2D tunneling spectroscopy aided
by magnetic or quantum-order excitations, and apply it to the description of
van-der-Waals heterostructures of graphene/ultrathin $\alpha-{\rm RuCl}_3$. We
study the behavior of both the differential conductance and the inelastic
electron tunneling spectrum (IETS) of these heterostructures. The IETS in
particular exhibits features, such as the gap of continuum spinon excitations
and Majorana bound states, whose energies scale {\it cubicly} with the applied
magnetic field. Such scaling, which exists for a relatively wide range of
fields, is at odds with the linear one exhibited by conventional magnons and
can be used to prove the existence of Kitaev quantum spin liquids.
