Iceplant, while considered drought tolerant, is a bad choice for slopes and bluffs because not only does it actually contribute to erosion but it is non-native and invasive. For slopes and bluffs consider native alternatives that have a deep root system such as Iva haysiana "San Diego Marsh Elder" or Baccharis Pigeon Point "Dwarf Coyote Bush" both of which are fire resistant as well!
For (extremely) detailed information about what to do (and what not to do) with your slope and a list of appropriate plants check out the following article by Bert Wilson of Las Pilitas Nursery: Slopes or visit Las Pilitas Nursery in Escondido for a printed list of appropriate slope plantings for San Diego County.