In several elementary particle scenarios, self-dual fields emerge as
fundamental degrees of freedom. Some examples are the D=2 chiral boson,
D=10 Type IIB supergravity and D=6 chiral tensor multiplet theory. For
those models, a fully satisfactory variational principle was missing until the
works of Ashoke Sen. We generalize this technique to the fermionic sector of
self-dual super Maxwell gauge theory in D=4 Euclidean spacetime both in the
component formalism and in the superspace. For the latter, we use the geometric
tools of rheonomy together with integral forms. We show the equivalence between
the two formulations by choosing a different integral form defined by means of
a Picture Changing Operator. That leads to a meaningful action functional for
the variational equations. In addition, we couple the model to a non-dynamical
gravitino in order to extend the analysis slightly beyond the rigid case. A
full-fledged self-dual supergravity analysis will be presented elsewhere.Comment: 15 pages, no figure