Step 1

Finely shred zest from 2 of the limes; juice to get 1/4 cup. In a small bowl whisk together 1 Tbsp. of the fish sauce, 1 Tbsp. of the sugar, lime zest, oil, and garlic. Place steak in a resealable plastic bag; pour mixture over steak. Seal bag, turning to coat. Marinate in refrigerator 15 minutes or up to 24 hours. Drain; discard marinade. Grill steak on rack of a covered grill directly over medium heat 15 to 18 minutes or until desired doneness. Cover. Let rest 5 minutes.

Step 2

Meanwhile, for dressing, in a small bowl whisk together lime juice, remaining fish sauce, remaining sugar, 1 tablespoon water, and red pepper. In a large bowl combine noodles, lettuce, cucumber, carrots, basil, and mint. Thinly slice steak against the grain; arrange on salad. Sprinkle with peanuts. Serve with dressing and remaining lime, cut into wedges.