In a blender, combine pineapple chunks, rice vinegar, 120 millilitres of water, granulated sugar, soy sauce, sambal oelek, and minced garlic. Blend until the mixture is smooth.

Pour the blended mixture into a saucepan over medium heat and bring it to a gentle boil.

In a small bowl, dissolve cornstarch in 30 millilitres of cool water to create a smooth slurry. Once your sauce reaches a boil, reduce heat to low and stir in the cornstarch slurry, mixing continuously until the sauce thickens, about 2 to 3 minutes.

Remove the pan from the heat and let the sauce cool. Transfer it to a sterilized jar or bottle and refrigerate until ready to serve.