You can do this but it has to be prior to them liking your page. There's an app that you can use to do this called 22 Social. You will then be able to pull your page like emails from people who come to like your page using an app you promote on Facebook. Pretty awesome stuff! It's also mobile friendly.
Your can get user ids from google chrome extension then put user ids in facebook ad campaign, targeted traffic for cheapest bid.
Yes, you can as long as the extension from google chrome will output a comma delimited format. Facebook allows this type of advertising because it's very targeted and causes people to click more often - which in turn gives your campaign cheaper clicks.