Heat a small dry skillet over medium heat. Add sunflower and caraway seeds and toast, stirring occasionally, for 3 minutes, or until the caraway releases a hint of its licorice fragrance. Pour the seeds into a small cup or ramekin and set aside to cool.
Using the same pan, add the vinegar and shredded onions. Cook the onions in the vinegar over medium heat for about 5 minutes, just until onions start to soften. It may cause your eyes to tear for a minute, and seems counterintuitive, but the vinegar tames and softens the sharpness of the onion. Set aside and let cool slightly.
In a small bowl, whisk together cumin, coriander, olive oil, Dijon mustard, and agave for a minute or two, until they emulsify into a creamy dressing. Keep the dressing until right before you’re ready to serve. Slaw should be crisp, not soggy.
In a large bowl toss together the shredded cabbage and carrot. Add the onions and any vinegar from the pan that hasn’t evaporated. Pour in the dressing and toss again. Finish with the chopped herbs and toasted caraway and sunflower seeds. Season generously with sea salt and pepper.