Combine soy sauce, rice vinegar, water, and sesame oil in a small saucepan and whisk to blend.

Place over medium-high heat and bring to a gentle simmer, about 1 minute.

Stir in minced garlic and ginger, whisking continuously for 30 seconds.

Add sugar and red chili flakes, stirring until sugar dissolves and heat is evenly distributed.

Let the sauce simmer for 30 seconds, then taste and adjust heat or tang by adding more chili flakes or sugar as desired.

In a small bowl, whisk together cornstarch and 1 tablespoon cold water to form a smooth slurry.

Slowly pour the cornstarch slurry into the simmering sauce while whisking constantly until the sauce thickens and becomes glossy, about 20 to 30 seconds.

Remove the saucepan from heat and stir in roasted peanuts, then season with salt and white pepper to taste.

Allow the sauce to cool for about 5 minutes before transferring to a clean glass jar for storage.