You can add the suffix "-ling" to many words to denote smallness. So a duckling is a small duck, hireling, foundling, hatchling, etc.
One slang expression for taking a bowel movement is to "take a dump."
Dumplings are cooked balls of dough (and yummy at that). But couldn't the word be taken to mean "little dumps"? Little shits? Little balls of shit? I'll never look at a Chinese menu the same again.