Is there any way to see the total data transferred as a report or dashboard widget? I know there are Bandwith Usage Over Time displays, but I'd like to see total data, not rates, both network-wide and per-AP. Any good way of gathering this data?
I will preface the following statement by saying that I am not a reporting expert, but in playing around with the dashboard widgets I think I have found two that suit your needs:
The "Top 10 Aerohive Devices by Wi-Fi Client Usage" will show you total data usage, at least for the top 10 devices, over the set interval of time. The "Usage by Location" will show you total network usage by, well, location, as defined by you.
By creating a customer perspective as I've done, you can click the gear icon to either export the data once or schedule the perspective data to be sent to you as a recurring report:
Unfortunately I wasn't able to think of a way to get data usage per AP for all devices (providing you have more than 10), but hopefully this is a start to get you what you need.