- Preheat a grill or grill pan over medium-high heat. Rub the flank steak with vegetable oil, salt, and black pepper. 
- Grill the steak for about 4-5 minutes on each side for medium-rare, or until it reaches your desired doneness. Remove from the grill and let it rest for 5 minutes. 
- While the steak is resting, prepare the salad. In a large bowl, combine cherry tomatoes, cucumber, red bell pepper, red onion, cilantro, and mint. 
- In a small bowl, whisk together lime juice, fish sauce, sugar, and red pepper flakes until the sugar is dissolved. 
- Slice the rested steak thinly against the grain and add it to the salad bowl. Pour the dressing over the salad and toss gently to combine. 
- Serve immediately, garnished with extra herbs if desired.