Lancer can mean start a mostly automated process, but not any kind of ongoing action. It probably acquired this meaning by analogy with its use to mean start a engine or a machine (lancer le moteur), itself an extension of the meaning to put animals in movement (lancer un cheval, ses bêtes) then motor vehicles.
Lancer un riz sounds strange to me, but rice cookers are rare around me. Lancer la cuisson is however commonplace, as would be *lancer l'enregistrement", lancer la lecture (d'une vidéo par exemple), lancer l'installation and so on. The common link here is that the process requires very little involvement of the subject, who started it and might stop it at some point, but isn't needed for it to complete.
It's also used very often for all kinds of machines and for computer programs (Lance Skype pour voir si il plante toujours), all by extension of the start an engine meaning.