In a small bowl, whisk vinegar, ginger, garlic, sugar, vegetable oil and 2 Tbsp. mint. Season with salt and pepper. In a large bowl, toss carrots, red onion, cranberries, scallions, cilantro and remaining 1/4 cup mint leaves. Pour dressing over salad, toss well and marinate at room temperature for about 1 hour, stirring occasionally, to allow flavors to develop.