To prepare sauce, place the first 11 ingredients in a food processor; process until finely chopped, scraping sides of bowl occasionally.
To prepare steak, sprinkle steak with 1/4 teaspoon salt and black pepper. Heat a cast-iron grill pan over high heat. Coat pan with cooking spray. Cook steak 4 minutes; turn and look for red beads forming on the surface to indicate the steak is approaching medium rare. Cook 4 minutes or until desired degree of doneness. Let rest 5 minutes. Cut steak diagonally across the grain into thin slices. Serve with sauce.
Wine Note: As far as wine is concerned, flank steak is a pretty easygoing partner--many red wines would work well--but the chermoula is a different story. Garlic, lime, paprika, cumin, cilantro, and coriander are all dominant seasonings that make this dish sizzle. But they can also make wine fizzle. Best bet: a soft, thick, fruit-driven red that will act to "cushion" all the spice. Try Geyser Peak's 2001 Shiraz from Sonoma County, California ($18). -Karen MacNeil