Salt the shredded cabbage with 1 teaspoon of salt. Toss well and let sit for 20 minutes. Squeeze out as much liquid as possible and pat dry.
Whisk all dressing ingredients together until completely smooth. Taste and adjust until creamy, tangy, and well seasoned.
Grate the carrots and slice the green onions and any other vegetables.
Combine the drained cabbage, carrot, green onions, red onion, and parsley in a large bowl. Toss to distribute evenly.
Pour three quarters of the dressing over the vegetables. Toss thoroughly to coat. Add more dressing as needed.
Taste and adjust seasoning boldly. Season more aggressively than feels necessary as cold temperatures mute flavors.
Cover tightly and refrigerate for at least 1 hour. Two hours or overnight is strongly recommended.
Before serving, stir well and taste and adjust with extra mayonnaise, salt, or vinegar as needed.
Transfer to a serving bowl. Garnish with fresh parsley and a dusting of smoked paprika. Serve cold.