Unused live electrical wires in kitchen
Assuming you don't want to/can't remove them completely, (i.e.- back to an existing junction box, or all the way back to the breaker box), you need to properly terminate them (capped with wire nuts) in an accessible junction box.

In other words- install a junction box in, put wire nuts on the wires, install your cabinets, with a hole where the junction box is, and put a cover plate on.