In a small bowl, whisk together soy sauce, lime juice, fish sauce, brown sugar, sriracha, and minced garlic until combined.

Pour the marinade over the flank steak in a resealable bag. Seal and refrigerate for at least 30 minutes.

Heat a grill pan over medium-high heat and add vegetable oil.

Grill the marinated steak for 3-5 minutes on each side for medium-rare.

Let the steak rest for 5 minutes, then slice against the grain.

In a large bowl, combine romaine lettuce, cherry tomatoes, red onion, cucumber, cilantro, and mint.

Transfer the salad mix to a platter, top with sliced steak and sprinkle roasted peanuts on top.

Serve with lime wedges on the side.