To prepare sauce, combine first 8 ingredients in a food processor; process until smooth. Place in a small bowl.
To prepare mojo, combine cilantro and next 5 ingredients (through 1 garlic clove) in a food processor; process until smooth. Place in a small bowl.
Remove brown gills from the undersides of portobello mushrooms using a spoon; discard gills. Cut each mushroom into 6 slices; set aside.
Steam green beans 3 minutes or until tender; keep warm.
Heat a nonstick grill pan over medium-high heat. Coat pan with cooking spray. Add steak; cook 2 minutes on each side or until browned. Remove from pan; cut steak diagonally across grain into thin slices. Toss mushrooms with half of soy mixture; add to pan. Stir-fry 1 minute; remove from pan. Return steak to pan; cook 2 minutes or until desired degree of doneness. Drizzle steak with remaining soy mixture. Arrange steak, mushrooms, and green beans on serving plates. Serve with mojo.