handful, to pick up with the fingers, to seize
摣 centers on grasping or taking hold of something with the hand, especially in a small quantity: picking up with the fingers, seizing, or taking a handful.
摣 combines 扌 (hand) with 虘, which likely contributes the sound and may relate to grasping or seizing. The exact historical development of 虘 is uncertain.
The hand radical 扌 beside 虘, which looks like a tiger's head 虍 over an eye 目, suggests a hand reaching out to seize something with precision, like picking up a small object with the fingers.
For サ, imagine a hand seizing a small sack of salt: sack -> サ, and the fingers pick up a handful.