Wash and dry all produce. Trim and thinly slice scallions, separating greens and whites. Halve cucumbers lengthwise, then slice into thin halfmoons and toss with 1 tsp sugar and 2 TBSP + 2 tsp vinegar (we sent more) in a small bowl. Season with salt and pepper and set aside. Pat chicken dry with a paper towel; cut into 1-inch pieces.

Heat a drizzle of oil in a large pan over medium-high heat. Add scallion whites and cabbage. Season with salt and pepper. Cook, tossing occasionally, until softened, 3-4 minutes. Remove pan from heat and stir in remaining vinegar. Transfer contents of pan to a medium bowl.

Heat a large drizzle of oil in same pan over medium-high heat. Add chicken and cook, tossing occasionally, until browned and cooked through, 4-6 minutes.

Reduce heat under pan to medium, then pour in bulgogi sauce. Bring to a simmer and let bubble until sauce has reduced slightly, about 2 minutes, while tossing chicken to coat. Stir in cabbage mixture, then remove pan from heat.

In another small bowl, stir together sour cream, 2 tsp water, and sriracha (to taste). (TIP: Add more water as needed to achieve a drizzly consistency.) Wrap tortillas in a damp paper towel and microwave on high until warm, about 30 seconds.

Divide chicken and cabbage mixture between tortillas, then top with cucumbers. Drizzle crema over each taco and sprinkle with scallion greens. TIP: Go easy on the crema for anyone who isn’t a fan of spicy flavors.