I would try adding a thickener - like 1 tsp of cornstarch. That is pretty common in Chinese sauces.

Are you trying to heat the beans after adding the sauce?
I would add the sauce to the warm beans and serve immediately.
Cornstarch needs to be cooked....when would you add and cook that?

Sorry, I didn't read carefully - I thought the sauce was being cooked.

So it is just being swished together, like a salad dressing. Then I'd shake the sauce to try to emulsify it, mince the garlic very finely (helps thicken), and even use a dressing-suitable thickener (anthem gum?)

Thank you for the replies!

Currently, it is just tossed like a salad and is very
good. I encourage you all to try this
very simple recipe! However, my DH prefers
his green beans hot. I don’t mind
cooking the sauce and adding corn starch – how much would you add?

Corn starch needs to be mixed with a liquid.....the only liquid in that recipe is 1 T of soy sauce. Unless you want to dilute the sauce with some broth....I suppose 1/4 tsp corn starch might make it thick enough.

You might consider swapping the brown sugar for some honey or agave and using less soy sauce, except full sodium, to compensate for the extra liquid.

This is a similar recipe with a cooked sauce and maybe it will do the trick ;-).

SPICY ASIAN GREEN BEANS

1 bag (14-oz. Green Giant Select frozen whole green beans (I use fresh)

Sauce:

1/4 c. orange juice

1 t. cornstarch

3 T. reduced-sodium soy sauce (I use Raw Coconut Aminos)

1/8 to 1/4 t. crushed red pepper flakes

1 small clove garlic, minced

Cook green beans as directed on bag. Drain; place in serving bowl.

Meanwhile, in 1 quart saucepan, mix all sauce ingredients until well blended. Heat to boiling. Reduce heat to low; simmer 1-2 minutes, stirring constantly, until thickened and clear.

Stir sauce into cooked green beans to coat.