Colloidal building blocks can assemble into many different crystal structures, yet selecting a specific lattice without redesigning the particles remains a central challenge in programmable self-assembly. Here we demonstrate that independent tuning of colloidal surface charge enables deterministic structure selection using a fixed pair of oppositely charged colloids. Micromolar additions of simple ionic surfactants independently adjust the surface charge of each colloidal species without significantly altering solution ionic strength, allowing the same building blocks to assemble into Th$_3$P$_4$-, CsCl-, Cu$_3$Au-, and Li$_3$Fe-like crystals, the last of which represents a previously unreported colloidal crystal structure. Experiments and molecular dynamics simulations reveal that structure selection is governed by the competition between Coulombic attraction and lattice-specific like-charge repulsion, establishing charge asymmetry as a general design parameter for ionic colloidal assembly.