1
general::
Start to talk or ask questions. For example, You've got more questions? Well, fire away. This expression originated in the 1600s as a military command to discharge firearms and was being transferred to other actions by the late 1700s. Also see FIRE OFF.
American Heritage Idioms
2
general::
Phrase(s): fire away (at someone)
Fig. to ask many questions of someone; to criticize someone severely. • When it came time for questions, the reporters began firing away at the mayor. • Members of the opposite party are always firing away at the president.
McGrawhill's American Idioms And Phrasal Verbs