Bring white wine vinegar to a simmer in a small saucepan over medium heat. Cook until reduced to 2 tablespoons, 4 to 6 minutes. Transfer to a large bowl and let cool completely, about 10 minutes. Whisk in sesame oil, vegetable oil, rice vinegar, soy sauce, sugar, ginger, and salt.
Add cabbage and carrots to the bowl with the dressing and toss to coat. Let stand 5 minutes. Add sesame seeds and scallions.
