扒 has two pronunciations: bā (to cling, to dig, to strip) and pá (to rake together, as in 扒手 pickpocket). The bā reading is more common in everyday speech.
Hand on the left signals a physical action of grabbing, raking or stripping. The radical groups 扒 with 抓 (grab), 拉 (pull) and 拨 (push aside) in the broad family of hand-on-thing verbs that fill everyday Chinese.
Carries the sound bā unchanged. The original meaning of 八 - to split apart, two strokes diverging - also matches the action: fingers splitting the husk from grain or the skin from a peel. Sound and shape line up perfectly.
