Seed jalapenos and set aside as many seeds as you need to make the sauce either mild, medium, hot, or super hot: No seeds=mild, seeds from 1 pepper= medium, seeds from 2 peppers=hot, seeds from 3 peppers=super hot.
Put all ingredients except jalapeno seeds, corn starch, and extra tablespoon of water in a blender and blend until smooth.
Pour mixture in a sauce pan, stir in jalapeno seeds, and bring to a boil. Immediately reduce heat to low and simmer for 15-20 minutes.
In a small bowl add water and cornstarch and mix until combined. Pour the cornstarch mixture in the sauce and mix until combined.
Simmer for an additional 4-5 minutes, or until desired consistency is reached.