Prepare the green seasoning by blending parsley, cilantro, garlic, olive oil, vinegar, salt, and pepper in a food processor until smooth.
Butterfly the flank steak to lay it flat, then pound it with a meat mallet to an even 1/2-inch thickness.
Spread the green seasoning evenly over the flattened steak, leaving a 1-inch border around the edges.
Layer the provolone cheese evenly over the green seasoning.
Tightly roll the steak against the grain into a log and secure it with butcher's twine at 1.5-inch intervals.
Slice between the ties to create individual spirals.
Preheat the grill to medium-high heat (400 degrees F).
Grill the spirals for 4 to 5 minutes per side until the internal temperature reaches 135 degrees F for medium-rare.
Rest for 5 minutes before removing the twine and serving.