Season beef with salt and pepper and place it into a ziptop bag.
In the bowl of a food processor combine herbs, garlic, red pepper and process until chopped fine but not pureed. Scrape mixture out into a large measuring cup. Add olive oil, vinegar and lime juice and stir until combined. Pour about 1 cup into a small serving bowl and reserve for later. Pour the rest over the beef in the zip top bag. Seal and marinate in the fridge for at least 2 hours.
Preheat grill to medium-high heat. Remove meat from ziptop bag and place onto hot grill. Discard marinade. Grill 5-6 minutes per side until desired doneness. Remove from grill, loosely tent with foil and let rest for 5-10 minutes. Slice meat across grain into long strips and serve with reserved chimichurri sauce and crusty bread.