It would be goof if we could run timers via dinnamicaly via code, programatically. Something like an Action receiving a timer name as parameter.
As Nuno Rolo explained it's possible updating the system tables, nevertheless, would be nice to have one system action to provide that functionality.
There is a document about Timer which has all the information about what table\entities Timer uses . You can simply control those entities and provide a interface to insert update your job details.