Do canned kidney beans contain Toxins?
If Wikipedia is to be trusted (and in this case, their source is the FDA), there is in fact a toxin in some raw beans, such as kidney beans.


  The toxic compound phytohaemagglutinin, a lectin, is present in many
  common bean varieties, but is especially concentrated in red kidney
  beans. White kidney beans contain about a third as much toxin as the
  red variety; broad beans (Vicia faba) contain 5 to 10% as much as red
  kidney beans.3
  
  Phytohaemagglutinin can be deactivated by boiling beans for ten
  minutes; the ten minutes at boiling point (100 °C (212 °F)) are
  sufficient to degrade the toxin, but not to cook the beans. For dry
  beans, the U.S. Food and Drug Administration (FDA) also recommends an
  initial soak of at least 5 hours in water, which should then be
  discarded.3


During the pressure-canning process beans undergo (they are fully cooked in the can), the toxin is certainly deactivated.  Canned beans are ready to eat, even cold, although they probably taste better hot, and with some flavor from a sauce or accompanying dish.

The danger would be in slow-cooking dry beans of this variety, which have never been previously cooked.