In a small bowl add all the marinade ingredients (minus steak) and whisk well. Pour the marinade in a ziploc bag, add steak and close the bag and toss around a bit. Place in the fridge and let the steak marinate for 4 hours or overnight. The longer it marinates the better it will taste.
Prepare the dressing, by mixing all dressing ingredients in a small bowl and whisking well.
Grill the steak to your preferred doneness, I prefer mine medium, so for medium I usually leave it 7 minutes per side. Let the steak rest for 10 minutes after you grilled, then slice the steak across the grain.
In a large bowl toss the lettuce, pepper, cucumber, mint and cilantro together then pour the dressing over and toss well. Arrange the salad on a platter and place the sliced steak over the salad, then top with chopped peanuts.
Prep time does not include time to marinate the steak.
If you know you may be storing leftovers - use your dressing accordingly. The steak salad will last longer in the fridge, up to 5 days, if it is undressed - no one wants a soggy salad! To store undressed salad, place in a large bowl, drape with paper towel to help collect moisture, and cover with plastic wrap.
Please keep in mind that nutritional information is a rough estimate and can vary greatly based on products used.