steel studded walls
If you take a trip to your local home store,you'll see what you're working with.Metal studs can be drilled fairly easily to accept screws,in fact,when the drywall is installed (hung) the screws used are self tapping (no pre-drilling required).When the studs are drilled to the footer and header,then drywall attached,you end up with a very sound surface on which you can mount cabinets.Everything kind of holds everything together.
If your wall is already covered you still have a few options. Depending on the weight of what you are hanging you use "hollow wall anchors" these can be toggle bolts (probably best) or the plastic anchors that expand behind the wall. If you are hanging substantial weight you can remove the drywall that will be hidden by your cabinets, install blocking, reinstall the drywall and then your cabinets. Another option would be to hang your cabinets and run a support from the cabinet to the floor on top of the drywall. You can dress it up or even use shelf supports to accomplish this.