hm, not that i know of. i also use a mac.
generally though if the DBE samples were generated by the tool, they will be in order, i think from top left to lower right, in columns. so if you need to delete a bunch of samples you can just click the first one in a column that you want to delete and then start hitting the delete key. DBE will automatically select the next sample down after it's deleted the current sample. in this case i think you have to use the real delete key if your keyboard has it, or i think Function-Backspace generates "delete" as well (but i cant test this because i don't use an apple keyboard)
rob