Clinically what's a easy way to distinguish noncyanotic from cyanotic congenital cardiac anomalies?

Yes possible. Differentiation between the two is mostly clinical. Cyanosis is bluish discoloration of tips of fingers, tongue etc. In some congenital anomalies of heart, there is an admixture of oxygenated and deoxygenated blood, when this occurs the cyanosis is clinically evident.