From sfgate article

The vinaigrette

• 1 tablespoon Dijon mustard
• 3 tablespoons red wine vinegar
• 1 teaspoon kosher salt
• 1/2 cup extra virgin olive oil

Vinaigrette:

1. Combine mustard, vinegar and salt in a bowl. Slowly whisk in olive oil until well blended.

The coleslaw

* 1 small red onion, very thinly sliced
* 1 cup red wine vinegar

* 2 jalapenos, seeded, cut in half and sliced crosswise
* 1/4 cup parsley, chopped
* 1/2 green cabbage, core and outer leaves removed, and very thinly sliced
* kosher salt 

The coleslaw:

1. Macerate onions in the cup of red wine vinegar, and let sit at least 20 minutes. Remove onions and discard vinegar.
2. Toss onions with jalapeno, parsley, cabbage and salt. Toss with vinaigrette until evenly coated.