Do you have a salad dressing recipe that fits this description?

I went to a Thai restaurant and as an appetizer they served julienne cabbage and carrots poured with a dressing. The dressing looks like a diluted shampoo, off white to lemon yellow in color and the taste somewhat is cross between a lemon juice and a Dunkin' Donuts lemon filling. It is sweet and soury but nice. I guessed it has milk in it or cornstarch to make it thick but not too thick. I asked the owner if its sold in the supermarket and she says it's an in'-house secret.