I found the answer after some googling!
In order to select multiple items by touch in any metro app, on each item you want selected, you swipe the item to the right.
so if I want to highlight emails 1, 3, 4, 7, 8 to copy them to an email folder, I would select email 1 with my finger, then I would swipe email 3 to the right, then swipe emails 4, 7, and 8 to the right as well. then move it to the folder by selecting the move button at the bottom of the screen.