  In proto-neutron stars with strong magnetic fields, the cross section for
$\nu_e$ ($\bar\nu_e$) absorption on neutrons (protons) depends on the local
magnetic field strength due to the quantization of energy levels for the $e^-$
($e^+$) produced in the final state. If the neutron star possesses an
asymmetric magnetic field topology in the sense that the magnitude of magnetic
field in the north pole is different from that in the south pole, then
asymmetric neutrino emission may be generated. We calculate the absorption
cross sections of $\nue$ and $\bnue$ in strong magnetic fields as a function of
the neutrino energy. These cross sections exhibit oscillatory behaviors which
occur because new Landau levels for the $e^-$ ($e^+$) become accessible as the
neutrino energy increases. By evaluating the appropriately averaged neutrino
opacities, we demonstrate that the change in the local neutrino flux due to the
modified opacities is rather small. To generate appreciable kick velocity
($\sim 300$ km~s$^{-1}$) to the newly-formed neutron star, the difference in
the field strengths at the two opposite poles of the star must be at least
$10^{16}$~G. We also consider the magnetic field effect on the spectral
neutrino energy fluxes. The oscillatory features in the absorption opacities
give rise to modulations in the emergent spectra of $\nu_e$ and $\bar\nu_e$.
