How do I farm cursed chests?
Solution 1:
Cursed chests do look different then regular chests. They kind of look like the demonic versions of the big golden 'Resplendent' chests.
Here's a picture of one: 
Apparently, however, many of these chests spawn in predetermined positions across all acts. See http://eu.battle.net/d3/en/forum/topic/9887928799 for details.
That being said, see this blue post that says: 'Cursed chests are similar to other events. They have some degree of randomness, such as where exactly in a dungeon they spawn (if they spawn at all)'