  We discuss quantum tunneling between classically BPS saturated solitons in
two-dimensional theories with N=2 supersymmetry and a compact space dimension.
Genuine BPS states form shortened multiplets of dimension two. In the models we
consider there are two degenerate shortened multiplets at the classical level,
but there is no obstruction to pairing up through quantum tunneling. The
tunneling amplitude in the imaginary time is described by instantons. We find
that the instanton is nothing but the 1/4 BPS saturated ``wall junction,''
considered previously in the literature in other contexts. Two central charges
of the superalgebra allow us to calculate the instanton action without finding
the explicit solution (it is checked, though, numerically, that the saturated
solution does exist). We present a quantum-mechanical interpretation of the
soliton tunneling.
