B4A stuff will work on Kindle Fire, but there is a screen resolution requirement, specific to them.. I'll try and dig out the email I had from Amazon about it. You will have to submit your App to the Amazon App Store as well. My first one is available on there, but will need another screen resolution to allow it to work with Kindle Fire.. It's on the list of things to do, which seems to be getting longer and longer at the moment!
ETA :
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To be compatible with Kindle Fire, apps must be optimized to run on a 7” screen with width: 600px and height: 1024px (Abstracted LCD Density: 160). Please note that the device will reserve 20px of the height to display a soft key menu, yielding a height of 1004px when in fullscreen mode.
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