Preheat the grill to medium-high heat. Toss the baby potatoes with a little olive oil and roast at 400F in the oven until tender, about 20 minutes.
Prepare the green herb sauce by whisking together the parsley, cilantro, minced garlic, olive oil, and red wine vinegar in a small bowl. Set aside.
Grill the beef flank steak for 5 to 7 minutes per side until it reaches your desired doneness. Let it rest for 10 minutes before slicing against the grain.
Grill the asparagus and corn until lightly charred. Slice the kernels off the cob and cut the asparagus into bite-sized pieces.
Assemble the dish by laying down a bed of arugula, topping it with the roasted potatoes, grilled vegetables, cherry tomatoes, sliced red onion, and the sliced beef. Drizzle generously with the prepared herb sauce.