Hi everyone,
Today, I was searching for a way to view and edit particles online and thought I remember a page under Corona’s domain name. It turned out that this was not the case because I mixed it up with the shader playground. Anyway, I asked for help on the Slack channel and got some solid recommendations from both Mark and roaminggamer and wanted to post those links to forums so others like me can find those links with a simple Google search.
Hope we saved you some time 
Particle Editors:
Here are the ones that Mark suggested:
– this one’s by Caleb P
– this one’s from roaminggamer
This one was from roaminggamer:
http://onebyonedesign.com/flash/particleeditor/
Lastly, here’s what I found and started using: http://particle2dx.com/
(You can use the .json file you got from this page and use it like the sample project you can find in here)