In a wide-mouth mason jar, combine the red wine vinegar, Dijon mustard, olive oil, honey, lemon juice, lemon zest, salt, and pepper. Secure the lid and shake vigorously until the dressing is smooth and emulsified. Alternatively, whisk everything together in a small bowl.
Add the purple cabbage, green cabbage, carrots, cilantro or parsley, jalapeño, and pepitas to a large bowl.
Pour the dressing over the slaw and toss really well with tongs until everything is evenly coated.
Taste and add more salt or pepper as needed. Serve immediately for the most crunch, or chill for 15 to 20 minutes to let the flavors meld and the cabbage soften slightly. Toss right before serving.