org-cycle command cycles between different states (folded, show children, show subtree, back to folded) so it isn't quite the same as having separate expand and collapse commands -- you don't need two key bindings since once expanded you can hit tab again to hide everything.
If you want to bind separate expand and collapse commands, you might use
org-show-subtree as your expand command, and use
outline-hide-subtree for the inverse operation. Note that those operate on the whole subtree so it's a bit different then
org-cycle which allows you to show just the children before showing the whole tree. I don't think there are equivalent "partial expand, then full expand" and "partial collapse, then full collapse" commands so you might need to write your own based on