Brush steaks all over with 2 tsp. oil; season. Grill over medium-high, turning once, until browned, 10 minutes for medium-rare. Transfer to cutting board; let rest 10 minutes. In small bowl, whisk 6 tbsp. oil and garlic. Drizzle escarole halves with 4 tbsp. garlic oil. Grill until charred, 3 minutes; season. Brush steak with 2 tbsp. garlic oil; thinly slice. Serve with escarole and lemon wedges to squeeze over greens.