Yes, preparing laser cut metal parts for painting is simple. Before you paint, roughen the surface with a Scotch Brite pad and then thoroughly clean the parts with acetone. (Make sure to wear gloves.)
For laser cut wood or plastic, just lightly clean off any dust or dirt that may have collected on the surface.
Keep in mind that painting is not a particularly durable or long lasting finish for your parts, and for that we recommend our online powder coating service.