I have a 16ml gap between the wall tiles and the granit counter top in my kitchen. I want to finish this gap properly. Can I get nery small boarder tiles? I can't seem to find any.

Small tiles do exist. You can get them glued to a mesh backing (such as 24 tiles by 24 tiles) and peel them off and use them individually, or buy thin 'accent' longer tiles, usually ceramic. You don't want border tiles because they have a rounded edge for being along a top row. You could also pay a specialty kitchen/bath place for a long strip of some composite material like Corian.

16 mm is a bit over 1/2" for us in the US. They are very common and are often called mosaic tile.