It's called Gamedevelop and can export to html5.
Runs on both windows and linux and has a very similar design to construct.
<img src="http://www.compilgames.net/img/content/big_events.jpg" border="0">
It is completely free and available for download for ubuntu users.
If you would like to support their development, please consider donating.
So in fact Scirra Construct has a free clone on linux and real competition too- because right now it is the only option for linux users. <img src="smileys/smiley36.gif" border="0" align="middle">
Did I mention that it is open source and completely free too?
Maybe not on par in terms of features, but definitely worth a try.
It would be interesting to see how many users it will gather. If I was Ashley, I would keep a close eye on it's userbase. Linux is turning into a very mainstream OS, with china making their own OS based on ubuntu, Valve adopting it for SteamOS and many other factors that are coming together.