It's a bit convoluted right now, but there are changes planned according to the TODO list, .? To close a Poll, go to the message and select Edit Poll from the More menu.? Once that page opens, the Close Poll button is at the bottom.? If you change your mind, you can go back to the same place and click Reopen Poll.
To limit the time it's open, sort of, you can edit the hashtag #Poll and set the Duration, then choose Lock Topic just below that.? Choices are One Hour, One Day, One Week, One Month, One Year, and Forever.? The limitations here are that the time will be the same for all polls and you can only Lock the topic, not close the poll.? You'd still need to follow the above to close it officially.
There's currently no way to have the results emailed to you, but it has been requested.? For now, you have to go to the message and look at who responded.
Duane
Duane