1. Combine 1 cup boiling water and chile in a small bowl; let stand 10 minutes or until hydrated. Drain; finely chop chile. Combine chile, 1 tablespoon oregano, 1 tablespoon juice, oil, and 1 teaspoon cumin in a zip-top plastic bag. Mince 4 garlic cloves; add to bag. Add steak to bag; seal. Shake to coat; refrigerate 1 hour.
2. Preheat oven to 450°.
3. Crush remaining 4 garlic cloves. Arrange crushed garlic, onion, and tomatillos in a single layer on a baking sheet coated with cooking spray; lightly coat vegetables with cooking spray. Bake at 450° for 20 minutes or until charred. Combine tomatillo mixture, remaining 2 tablespoons oregano, remaining 1 tablespoon juice, remaining 1/2 teaspoon cumin, 1/2 teaspoon salt, 1/4 teaspoon pepper, and sugar in a blender; process until smooth, scraping sides.
4. Preheat the grill to high heat.
5. Remove steak from bag; sprinkle both sides of steak evenly with remaining 1/2 teaspoon salt and remaining 1/2 teaspoon pepper. Place steak on grill rack coated with cooking spray. Grill 2 minutes on each side or until a thermometer inserted into the thickest portion of steak registers 135° or until desired degree of doneness. Let steak stand 10 minutes. Cut steak diagonally across grain into thin slices. Place 3 ounces steak on each of 4 plates. Top each serving with about 3 tablespoons sauce; sprinkle each serving with 1 1/2 teaspoons cilantro.