If you can go around the glass just go around the glass. Slicks are just as tough as knobies they just don't have knobs, put tire liners in if you want to avoid flats from glass thorns and nails.(Liners are tougher than kevlar belted tires anyhow.)
26" x 1.4 or wider slicks, will work very well on packed crushed rock and dirt.
Slickasaurus is a very nice tire. So are the Michelin country rock[1.75], Ritchy tom slick[1.4], Kenda K841[1.95] and Kenda K-rad[2.3]. None of them are of the flat resistant type though so useing tire liners is recommended.