Theyre not a texture, or at least, arent replaceable as such. I tried removing them long ago too; the only way to do so (aside from editing core parts of the game, anyway) is to use normal or minimal settings- something thats worked out fine for me, since i wanted to remove almost every other piece of eye candy as well, and those dots arent the only thing that cant be disabled on enhanced and premium modes.
Nevertheless, itd probably be nice to get full control over every component of the onscreen visuals in some future update.