Yeah KA doesn't have an auto-sell included. You can setup your Loot.ini (macros folder) to destroy trash items though. Or like Sic mentioned, just take a break and open a vendor and "/autoloot sell"
It's also nice to make a mq2autoloot hotkey that you can use to easily add items to the destroy list. If you have an item on your cursor and hit this hotkey, it will destroy it and any more you loot:
/setitem destroy