  In this paper, we first extend the micro-macro decomposition method for
multiscale kinetic equations from the BGK model to general collisional kinetic
equations, including the Boltzmann and the Fokker-Planck Landau equations. The
main idea is to use a relation between the (numerically stiff) linearized
collision operator with the nonlinear quadratic ones, the later's stiffness can
be overcome using the BGK penalization method of Filbet and Jin for the
Boltzmann, or the linear Fokker-Planck penalization method of Jin and Yan for
the Fokker-Planck Landau equations. Such a scheme allows the computation of
multiscale collisional kinetic equations efficiently in all regimes, including
the fluid regime in which the fluid dynamic behavior can be correctly computed
even without resolving the small Knudsen number. A distinguished feature of
these schemes is that although they contain implicit terms, they can be
implemented explicitly. These schemes preserve the moments (mass, momentum and
energy) exactly thanks to the use of the macroscopic system which is naturally
in a conservative form. We further utilize this conservation property for more
general kinetic systems, using the Vlasov-Amp\'{e}re and
Vlasov-Amp\'{e}re-Boltzmann systems as examples. The main idea is to evolve
both the kinetic equation for the probability density distribution and the
moment system, the later naturally induces a scheme that conserves exactly the
moments numerically if they are physically conserved.
