So-and-so poking face using fingers (7)
I believe the answer is:
digital
'using fingers' is the definition.
(I've seen this before)
'so-and-so poking face' is the wordplay.
'so-and-so' becomes 'git' (I can't justify this - if you can you should give a lot more credence to this answer).
'poking' means one lot of letters goes inside another (poke can mean to create a hole in).
'face' becomes 'dial' (face of a clock).
'git' placed within 'dial' is 'DIGITAL'.
Can you help me to learn more?
(Other definitions for digital that I've seen before include "finger" , "of modern clock?" , "Displaying in numbers like some watches" , "Type of clock" , "numerical information" .)