Thank-you for your question which brought back a few memories!
The cartoon I believe you are looking for is "Murun Buchstansangur".
There is not much available online about this character (and his
series) but here are a few sites to get you going in your search to
"Murun Buchstansangur was an odd fellow. Quite apart from his odd name
he was also very odd looking. He was a small grey onion-shaped man
with a mop of hair and clog boots. He lived under the dirty kitchen
sink of an end-terrace house in a rather dreary, rain-swept suburb.
Murun didn't have adventures, as such, rather he found himself with
dilemmas, events and decisions to ponder as he mooched through the day
with his friends and associates..."
"Murun Buchstansangur was a gentle but most unusual animation, often
shown as a gap filler between programs. Only one episode is presented
here but I am sure I have more somewhere. The story concerned the
life, loves and adventures of a little character who lived underneath
the kitchen sink in a house on a street corner. I do not know what
Murun was and I cannot for the life of me think of something which to
compare him to. Needless to say his world was very different to ours
in terms of the size. Murun was very small (you can get some idea of
his size in the picture below which shows him beside a public
telephone). He was not the only one of his kind as several of his
species popped up in other stories. He also had family but they did
not live with him. He had a lot of friends especially of the female
variety, all of whom were human in form but similar in height / size
to Murun. He interacted with most human sized objects e.g. phones and
even went out to the theatre and restaurant. However, we never see any
normal sized humans in any of the episodes. The series copyright was
1985 but I taped most episodes between 1994 and 1995 from Channel 4."
I hope this satisfies your curiosity and good luck tracking down some
more of this hidden cartoon gem. Should you require any further
assistance on this subject please ask for clarification and I will do
my best to respond swiftly.