SLA do not require a focus but can they use a focus. This concerns things like scrying SLAs and special items that when used as a foci, affect the spell. Link to example item below.
http://www.archivesofnethys.com/MagicWondrousDisplay.aspx?FinalName=Cauldro n%20of%20Overwhelming%20Allies
"A spell-like ability has no verbal, somatic, or material component, nor does it require a focus. "