So you want a red circle with a thin transparent outline?

If this is the case, there is a high chance that the transparent paper for dark shirts does not exist. The reason for this is that most inks used to print transfers/shirts are translucent, meaning they are not completely opaque. When printing on a dark shirt, you will need an opaque paper (a white canvas) for dark shirts. If the dark paper is not opaque, the inks will most likely not show up especially on a black shirt.

 

You can also make a black outline around the red circle and trim very close on the black outline. This will give a "transparent" effect. What kind of Opaque transfer paper are you using?