Since the removal of Google's "Instant search", it is no longer possible to tab through the results. This plugin will add back in that functionality.
The extension can be found here.
The keys to note are TAB, DOWN ARROW and the UP ARROW, this will cycle through all of the result links on the page. Click enter to go to that result.
The link selectors for what I consider a "clickable result" are a bit vague due to the markup that Google Search responds with. If you find examples of results that don't allow you to tab to the point you want, please open an issue with the results page you're trying.