With these cheapo lights, it didn't take much effort to get them apart.
I ran a heat gun around the edge until it was damn near too hot to touch. I made sure I didn't sit the heat gun on one spot otherwise the housing would start to bubble. As I progressively heat up the edge, I would pause randomly and attempt to seperate the lens to see if it was hot enough. Once it got hot enough, I just unhooked the two top and two bottom hooks (not quite as easy as I make it sound) and carefully pulled/pried the lens apart. Once I had enough to grab on the end it came off quick.
Then, I used the gun again to heat up the glue that was left in the housing channel and scraped it out with a flat head screw driver.
It probably took me about 20 minutes to pull the first one apart and about 10 for the second.