We study two-dimensional N =(0, 2) supersymmetric gauged linear sigma models (GLSMs) using supersymmetric localization. We consider N =(0, 2) theories with an R-symmetry, which can always be defined on curved space by a pseudotopological twist while preserving one of the two supercharges of flat space. For GLSMs which are deformations of N =(2, 2) GLSMs and retain a Coulomb branch, we consider the A/2-twist and compute the genus-zero correlation functions of certain pseudo-chiral operators, which generalize the simplest twisted chiral ring operators away from the N =(2, 2) locus. These correlation functions can be written in terms of a certain residue operation on the Coulomb branch, generalizing the Jeffrey-Kirwan residue prescription relevant for the N =(2, 2) locus. For abelian GLSMs, we reproduce existing results with new formulas that render the quantum sheaf cohomology relations and other properties manifest. For non-abelian GLSMs, our methods lead to new results. As an example, we briefly discuss the quantum sheaf cohomology of the Grassmannian manifold. Keywords: Supersymmetry, Topological Field Theory. A. Conventions and review of N =(0, 2) supersymmetry 40 A.1 Curved space conventions 40 A.2 N =(0, 2) supersymmetry in flat space 40 B. Elementary properties of the Grothendieck residue 43 C. One-loop determinants 44 C.1 Matter determinant for A/2-twisted GLSM with (2, 2) locus 44 C.2 Matter determinant for the B/2-twisted model 46 D.Čech-cohomology-based results for the correlation functions 46 D.1 P 1 × P 1 46 D.2Čech-cohomology-based results for F 1 49 R[E I ] = r I + 1 , R[J I ] = 1 − r I , (2.49) and such that Tr( Λ I E I ) and Tr(Λ I J I ) are gauge invariant.Anomaly cancelation imposes further constraints on the matter content and on the R-charge assignment. Let us decompose the gauge algebra g into semi-simple factors g α