Preheat one part of your grill to high heat and the other to lower heat. (The hot area of the grill is hot enough when you can hold your hand over it for only a second)
Stir together 1 teaspoon salt, 1/2 teaspoon ground cumin, 1/2 teaspoon ground coriander seeds, and 1/4 teaspoon black pepper.
Remove the steak from the marinade, pat dry, and rub the herbs all over the steak.
Put the prepared steak on the hot area of the grill. Grill for 1-2 minutes on each side to get a nice sear.
Then move the steak to the lower heated side of the grill. Cover, and cook for a few more minutes or until the steak is at your desired temperature.
Remove steak and let rest on a cutting board (covered with foil) for 10 minutes.
Slice against the grain and serve with chimichurri.