Whisk together olive oil, lemon juice, garlic powder, oregano, salt, and pepper in a shallow bowl. Add the chicken and set aside to marinade while you prep the rest of the ingredients and preheat the grill.
Cut romaine in halves or fourths and brush lightly with olive oil.
2 to 3 romaine hearts
Cut roll in half and brush cut sides lightly with oil, then season with salt and pepper.
1 ciabatta or sourdough roll
Grill chicken for about 5 minutes on each side, until cooked through. Remove and set aside, tenting to keep warm.
Add romaine and roll halves, cut-side down, and grill for about 2 minutes, until romaine has wilted slightly and roll is toasty.
To serve, chop the romaine and add to a large bowl. Slice the chicken, and cube the toasted bread. Add to the bowl. Toss with dressing and top with shaved parmesan.