Best way to power 2 motors with 1 power supply?
A parallel configuration is best, because then the current of one does not affect the other motor. The current will be doubled so you'll need a power supply that can handle twice the current than that of one motor.  If one motor draws 0.1A then two in parallel will draw 0.2A


  Or, perhaps, would it be best to power the 2 motors in series with a
  24-volt power supply?


Not a good idea.