Theres 22 street lights on Oltanis, all of which have to be done in a single life, meaning if you die, you have to start again.
The first 8 around the landing pad, 4 in the area next to the landing pad and the remaing ones are throughout the various routes.
With the first dozen near your ship, you can use either your wrench or blaster. The easiest way of taking the rest out is by using the devastator and visibomb, and given how easy it is to die on this level, it's worth stocking up on ammo before you start to save doubling back to a vendor.