a japanese cold noodle soup?

what is that soup called that is cold with cucumbers and it tastes like vinegar or something in it. the noodles are white and the liquid is clear. starts with an s i think. senunan or something like that. i want to make it at home, any recipes too?
the reason i’m saying its japanese is both times i’ve had it were when i went out for sushi. so i’m pretty positive it is japanese

Not too sure about japanese.. but I have heard of chilled cucumber soup. It’s a little dish from Egypt.

Japanese Noodles: Udon