How to hide a list in Designer:
In List settings-> General Settings
1) Uncheck option “Display this list on quick launch”. [This is necessary]
2) Check the “Hide from browser”.
3) Save the list.
Open it SharePoint site in browser and check that your list is hidden now.
How to open hidden list and unhide it in Designer:
1) Open SharePoint designer 2010.
2) Click the “All Files” folder at the bottom in left pane.
3) Right click your hidden list from “All Files -> Lists” folder and choose property.
4) Now you have your hidden list open in SPD.
5) In List settings-> General Settings: Uncheck the “Hide from browser” and save.