Multilayer stacks of twisted optical metasurfaces are considered as a
prospective platform for chiral nanophotonic devices. Such structures are
primarily used for the realization of circularly polarized light sources,
artificial optical rotation, and circular dichroism. At the same time, the
behavior of their hybrid photonic modes is strongly affected by the
moir\'e-pattern of superimposed periodic constituents. In this work, we show
that moir\'e-periodicity in bilayer dielectric photonic crystal slabs leads to
an arise of unlimitedly narrow optical resonances, which are very sensitive to
the relative twist and gap width between the sublayers. We demonstrate the
structure providing twist-tuning of the hybrid mode wavelength in the range of
300--600~nm with quality factor varying from~102~up~to~105
correspondingly. The obtained results pave the wave for the utilization of
moir\'e-assisted effects in multilayer photonic crystal slabs