The app icons in your Corona project directory are not applicable when doing native Android development. You need to follow Google’s Android documentation on how to add an app icon… or what Google refers to as a launcher icon.
First, you are right, you need to add an “android:icon” attribute to your <application> tag to reference launcher icon under your Android application project’s “res” directory.
http://developer.android.com/guide/topics/manifest/application-element.html#icon
You’ll of course need multiple resolutions of your app/launcher icon PNG. All of these PNG files *must* have the same file name (ie: “icon.png”) and you are expected to put them under different “res/drawable” subfolders indicating which DPI they support. For example:
res/drawable-ldpi/icon.png
res/drawable-mdpi/icon.png
res/drawable-hdpi/icon.png
res/drawable-xhdpi/icon.png
…etc…
Your AndroidManifest.xml file would then reference these icons like this…
<application android:icon="@drawable/icon">
Note that the above does not include the file’s extension.
Google documents resources and icon resolutions for different DPIs here…
http://developer.android.com/guide/practices/screens_support.html
I hope this helps!