The endoscopic endonasal approach to the orbit or the lateral recess of the sphenoid may require passing instruments through a transfixing trans-septal corridor to obtain an adequate working angle. However, this maneuver incurs non-negligible morbidity, with septal perforation, synechia and olfactory disorder. The “sliding windows” technique aims to reconcile optimal exposure with mucosal preservation. It is a safe alternative to wide septectomy, while preserving septal trophicity and olfactory function. It is based on asymmetric mucoperichondrial flaps and a central osteocartilaginous window, providing trans-septal access, without direct mucosal incision. By reducing denuded areas and ensuring double mucosal coverage, it can decrease the incidence of perforation and of the functional sequelae reported after conventional transfixing approaches. Three variants are described, depending on the needs for reconstruction and the extent of the approach: (1) unilateral septal flap; (2) asymmetric bilateral septal flaps; (3) asymmetric bilateral flaps, using the ipsilateral flap for reconstruction of the operative site at the end of the procedure. The “sliding windows” technique thus meets the aims of endoscopic endonasal surgery, in which functional preservation is a priority.