Preheat a large grill pan or heavy skillet over medium-high heat and lightly coat with cooking spray.
Season the flank steak evenly with salt and pepper on both sides.
Cook the steak in the hot pan 4 minutes per side for medium-rare to medium, or until it reaches your desired doneness.
Remove the steak from the pan and let it rest for 5 minutes, then slice thinly across the grain.
In a small bowl, whisk together the lime juice, brown sugar, soy sauce, fish sauce, minced garlic, and Sriracha to make the dressing.
In a large bowl, combine the sliced cabbage or greens, bean sprouts, julienned carrots, mint, cilantro, and basil.
Add 6 tablespoons of the dressing to the cabbage mixture and toss to coat evenly.
Toss the sliced steak with the remaining 2 tablespoons of dressing, then add the steak to the salad and toss gently to combine.