I am about to adjust the lash on my 1.6l 96 sidekick and I am wondering if I need to get the special tool mentioned in the manual or if I can do this with regular tools?

If you are talking about the special angled feeler gauges......then just regular flat ones will work fine (those are the ones I use anyway).

I am about to adjust the lash on my 1.6l 96 sidekick and I am wondering if I need to get the special tool mentioned in the manual or if I can do this with regular tools?

For my  Tracker, I welded a nut on a 3/8 drive socket and used a cabinet tipped screwdriver thru the opening to hold the adjuster while tightening the nut/socket with a wrench.  If the welded nut is big enough, you'll still be able to the socket with a rachet ,albeit, with an extension.  Good luck