Combine vinegar, 3/4 cup water, sugar, garlic, ginger, sambal oelek, and soy sauce in a small saucepan.

Bring the mixture to a boil over medium-high heat, stirring until the sugar is fully dissolved.

Reduce heat to medium and simmer the mixture for approximately 5 minutes.

In a separate small bowl, whisk together the cornstarch and 2 tablespoons of cold water to create a slurry.

Gradually whisk the cornstarch slurry into the simmering sauce.

Continue to simmer for 2 to 3 minutes until the sauce thickens and reaches a glossy, translucent appearance.

Remove from heat and allow the sauce to cool completely at room temperature.