  The absence of supersymmetric particles at the weak scale is a puzzle if
supersymmetry solves the gauge hierarchy problem. We show that, if the
right-handed neutrino masses arise from hidden gaugino condensation via
GUT-suppressed operators, successful thermal leptogenesis leads to the lower
bound on the gravitino mass, which may explain the little hierarchy problem. If
domain walls associated with the gaugino condensation are formed after
inflation, they annihilate when $H \sim m_{3/2}$. We address the possibility
that observable gravitational wave signals might emerge from the domain wall
annihilation.
