The most common and most likely answer to this crossword clue is the 6 letter word PINKIE
I've seen this crossword clue in The Guardian
P
I
N
K
I
E
Buddy explains!

The straight part
We know that "part of a hand" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case part of a hand = pinkie.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does PINKIE mean?
PINKIE noun- A little finger, the finger furthest on a hand from the thumb.
- (less commonly) A little toe, the toe furthest on a foot from the big toe.
- Methylated spirits mixed with red wine or Condy's crystals.
- A baby mouse, especially when used as food for a snake, etc.
- A white person.
- The Australasian snapper or pink snapper (Chrysophrys auratus).
- The smallest finger or toe of a hand or foot.
- (South Australia) A bilby.