Most kitchen windows are at the rear of the sink unit and are largely out of reach for many people; our client was one and needed to open the window for ventilation.
The solution was to make a long handled lever from solvent weldable plastic pipe and fittings to which a short length of pipe to go over the window opener handle is loosely attached. The pipe that goes over the handle has a flat piece of plastic welded to it to allow it to partially rotate around a screw joining it to a similar part on the operating lever. An extension to the operating lever part carries an adjustable screw to operate the window latch; the latch is first released by raising the lever and then the window is opened by moving the lever to the side.
The window can now be opened.