Add orange juice, sugar (or honey), gluten-free soy sauce, rice vinegar, garlic, and ginger to a small saucepan.
Place the saucepan over medium heat and bring the mixture to a gentle simmer, stirring occasionally.
In a small bowl, whisk together cornstarch and water to form a smooth slurry.
Slowly pour the slurry into the simmering sauce while whisking continuously.
Reduce heat to low and cook for 1–2 minutes, until the sauce thickens and becomes glossy.
Remove from heat and use immediately, or let cool slightly before storing.