I don't have a salt spoon, I don't think. I have 3 tiny mustard spoons and the handles wouldn't be long enough. They're only about 2.5" long in total. You'd still have the trouble of getting fingertips holding the handle in deep enough. There is a narrowing at the inner "rim" of the glass bowl and they're slightly bulbous at the base. The angle at which it is held in the holder does suggest "offering a toothpick" to me.
I only know it as Christine's piece and have always thought it was a toothpick holder - I just didn't bother trying to think of anything else it could be, it seemed so right.