If you are talking about sheets within the same document, you can have something like this pop up whenever you hit a keyboard shortcut (in my case shift-command-j):
This is done via a Jump to Sheet Automator Service (Dropbox download). To install just doubleclick the .workflow package and (if needed) click 'Download Anyway' in System Preferences > Privacy & Security.
This will cause a new item to appear in your Numbers > Services menu. Then, if you want a keyboard shortcut, go here in System Preferences and add one:
You can rename or remove the service by holding down the option key in Finder and choosing Go > Library > Services. You can also view the AppleScript contaned within the service by opening the .workflow package in Automator.
This particular service jumps to the first cell of the first table of the sheet you choose from an automatically generated list of all sheets in the current document. Using simple AppleScripts it is also quite easy to "jump" to any cell in the current document, to cells in other Numbers documents, or even to non-Numbers files on your Mac.
SG