In a large gallon-sized zip lock bag, add all the ingredients of the marinade and add the steak. Let marinade in the fridge overnight, or at least 2 hours.
When ready to cook, remove the steak from the fridge and bring to room temperature for about 30 minutes. Heat grill to medium high, remove the steak from marinade and pat dry with a paper towel. Sear the steak about 4-6 minutes on each side, depending on the thickness for medium rare. Remove, and let rest 10 minutes before slicing against the grain.
To make the dressing, whisk all ingredients in a small bowl, and set aside.
In a large bowl, add all the salad ingredients. Toss with a couple tablespoons of the dressing to coat. To serve, top with sliced flank steak.
Recipe by Amy vs Food at https://www.amyvsfood.com/2016/09/15/__skirtsteak/