Separately tie 2 bunches Tuscan kale around the stems with kitchen twine. Drizzle each bundle with 1 teaspoon olive oil and rub all over to coat the leaves. Grill over medium heat, turning, until well marked and starting to wilt, 2 to 3 minutes. Transfer to a cutting board; tear off the leaves and thinly slice. Toss with Caesar dressing and top with grated parmesan and croutons.