Although it is quite hidden, finding the id of a post and or page is easy.
At your admin side, go to Pages. You should see a list of the static pages available.
Click on the one that you want to get the id for. The Page ID is hidden in the URL. Look for post= and the number to the right of it is your Page ID.
To find the page id for a post just repeat the same process, clicking on a post this time.