To begin, add the soy sauce (or coconut aminos), rice wine vinegar, sesame oil, mashed garlic, grated ginger, and sriracha to a small bowl.
Whisk well until fully combined. Taste and adjust as needed—add more vinegar for brightness, more sriracha for heat, or a splash more soy sauce for salt.
Finish by stirring in sesame seeds and sliced green onions, if using. Serve immediately or refrigerate until ready to use.