I used the following method in asp.net to retrieve all caches (then I remove some caches based on the regular expression pattern).
IDictionaryEnumerator caches = HttpContext.Current.Cache.GetEnumerator();
I found GetObjects* but they are only available in Windows Sever AppFabric.
Is there any equivalent in Windows Azure AppFabric Caching?
In its current manifestation, no. You will need to know which keys there are/you need to get and set appropriate timeouts if you don't want to keep track of your cache items. Also missing are regions, tags and notifications which (for many use-cases) would offer a perfect workaround/efficient alternative to getting all cache-items or keys.
If you are unhappy with the state of azure caching you could put your frustration here or there.
With latest release of Windows Azure Caching (Preview) along with Windows Azure SDK 1.7, you have all the features that were available in on-premise Windows AppFabric Caching product.
Such as: Notifications, Regions, Tags, High Availability, etc.
The Windows Azure Caching (preview) does not have any extra cost other than the compute cost.
Please look into http://msdn.microsoft.com/en-us/library/windowsazure/hh914153.aspx for more details.