I don't see a way to send a report once. You can only subscribe people to regular reports from what I can tell. I'm not sure what time of the day they are sent as well.
Hey Adam, you can't specify the time of day you'd like the report to be sent for subscriptions... If you want to do a one-off send, you basically set up the subscription, select "send this report now" (little mail with green arrow in the subscription list), and then cancel the subscription. This will send the report right then.
Definitely would be nice to do a one-off send less manually.
The issue with this approach is that you still need to remember - let's say, four days after an email send - to set this up and execute it (and then delete it). This would eliminate the manual effort that's described here: