I use hoisin sauce, rice vinegar, orange juice, soy sauce and a bit of sesame oil - I’m not sure of amounts, I taste as I go, until I have a sharp-sweet salad dressing
Unfortunately most shop bought hoisin sauces aren't gluten free and most soy sauce isn't gluten free.
I often make my own hoisin sauce using an adapted version of BBC recipe but it needs lots of different ingredients which if OP doesn't do a lot of that type of cooking she might not have. However recipe is below and it is extremely tasty with shredded duck and spring onions in whatever spring roll/gf wrap etc that you prefer.
4 tbsp gluten free soy sauce
2 tbsp smooth peanut butter
1 tbsp dark brown sugar
2 tsp rice wine vinegar (although I usually use cider vinegar or white vinegar)
1 garlic clove, finely crushed (I use 1 cube of frozen garlic)
2 tsp sesame oil
⅛ tsp black pepper
1/2 tsp of Chinese 5 spice (check it's gluten free, most are)
Mix the whole lot in a microwaveable mug and then nuke it in the microwave until it's thickened (will thicken more as it cools but it needs to be bubbling when it comes out of the microwave - usually about 3 mins but I do it a minute at a time).
If I'm doing duck specifically for shredded duck then I usually rub Chinese five spice and salt onto the skin before cooking.