throw ground, know, be familiar
摜 centers on the idea of handling something repeatedly until it becomes second nature: throwing something to the ground as a practiced action, knowing it thoroughly, or being familiar with it through habit.
摜 combines 扌 (hand) with 貫, which likely contributes the sound and the idea of passing through or becoming accustomed. The exact historical development is uncertain.
The hand 扌 beside 貫 (pierce, pass through) suggests a hand that has done something so many times it goes through the motions automatically: throwing, knowing, being familiar.
For カン, imagine a can being thrown to the ground over and over until you know its sound by heart: can -> カン, and your hand is so familiar with the motion.