to dust, duster
撣 centers on the action of dusting or brushing off particles, and by extension the tool used for it: a duster.
撣 combines 扌 (hand) with 單, which likely contributes the sound. The character is associated with dusting or brushing by hand.
The hand radical 扌 beside 單 suggests a hand holding a simple tool. Imagine using your hand to dust off a surface with a duster.
For タン, picture dusting a tan leather couch: tan -> タン, and your hand brushes away the dust.