SQL Azure dm_exec_query_stats clearing?
Old question I know, but if anyone is still looking for one potential workaround...

I wrote a small utility (shared on my blog) that makes life easier when working with this DMV.  This utility takes a baseline of the query stats to act as an effective zero.

The utility then queries the DMV repeatedly and works out the changes to show what has executed over the time since the last call into the DMV.

For more details, see:
http://cbailiss.wordpress.com/2014/10/01/free-tool-sql-workload-profiler-for-on-premise-and-azure-sql-db/