  We perform a comprehensive SU(3)-flavor analysis of charmed mesons decaying
to two pseudoscalar SU(3)-octet mesons. Taking into account SU(3)-breaking
effects induced by the splitting of the quark masses, m_s != m_{u,d}, we find
that existing data can be described by SU(3)-breaking of the order 30%. The
requisite penguin enhancement to accomodate all data on CP violation tends to
be even larger than the one extracted from Delta a_{CP}^{dir}(K^+K^-,pi^+pi^-)
alone, strengthening explanations beyond the standard model. Despite the large
number of matrix elements, correlations between CP asymmetries allow
potentially to differentiate between different scenarios for the underlying
dynamics, as well as between the standard model and various extensions
characterized by SU(3) symmetry and its subgroups. We investigate how improved
measurements of the direct CP asymmetries in singly-Cabibbo-suppressed decays
can further substantiate the interpretation of the data. We show that
particularly informative are the asymmetries in D->pi^+pi^- versus D->K^+K^-,
D_s->K_S pi^+ versus D^+->K_S K^+, D^+->pi^+ pi^0, D->pi^0pi^0, and D->K_S K_S.
