1 bunch (6 large) scallions, trimmed and thinly sliced
2 (16-ounce) bags coleslaw mix or 1 (16-ounce) bag each of shredded green and shredded red cabbage
1 small red onion, thinly sliced
1/4 cup soy sauce
1/4 cup lemon juice
1/4 cup vegetable oil
2 tablespoons grated fresh ginger (from about a 1-inch piece)
2 tablespoons white vinegar
2 tablespoons dark brown sugar
2 teaspoons Asian sesame oil
2 teaspoons sesame seeds, optional
1 teaspoon salt
20 grinds black pepper