The SI hatch had rear speakers... they were to the sides of the rear seat... below the window. The wires are there, you have to pull the panel off and reach down inside, you'll feel a wire harness and there is a wire with a connector taped to it... those are your speaker wires. You can go to a junk yard and get the panels with the speaker grilles in them and the mounting hardware for the speakers... or try
www.hondaautomotiveparts.com, when you search for the parts just be sure to look under a 95 SI hatch, instead of your model... they wont list the proper parts for the lower models.