I’m sorry if I’m misunderstanding things here. Also, it may be a good idea to propose a simple change to the documentation that building for Android also generates an .aab file which is the one you should upload to Google Play. You don’t need to change anything in your code for that.
-- let's say you have img.png file under assets folder
local img = display.newImageRect("assets/img.png", 100, 100)
-- https://docs.coronalabs.com/api/library/display/newImageRect.html
If you are looking to replace OBB with Play Asset Delivery, this is not yet supported but probably, will be available later this year as Vlad stated here - Solar2D First Anniversary!