That is a noodle strainer. I have never thought that it would be used to hang on the side of a pan but I suppose if you had the right pan.... Someone with more knowledge of Japanese kitchenware will surely jump in here and fill in the blanks. It is quite small, perhaps the size of a Japanese tea cup.
While shopping in this Japanese dollar store I got the sense that I had entered the world of lilliputians. It wasn’t “Honey, I Shrunk the Kids”, but honey, I shrunk all the kitchenware. So much seemed to have been miniaturized.
Yes the item you think is a grilling gizmo is for serving cold noodles. If you do a search on ‘zaru’ you will see that they are normally round rather than square. I fancied a square one.