Preheat broiler on high.
Pull white and dark meat from chicken and set aside.
Slice the whole grain loaf lengthwise. Lay the halves on a baking sheet cut sides up, drizzle lightly with extra virgin olive oil and toast under the broiler til the edges turn a golden brown.
Start constructing your sandwich by slathering the bottom half of the loaf with Roasted Garlic Aioli. Then, spread the Fennel Mustard on the top half of the loaf. Continue by placing a layer of pulled, roasted chicken on the aioli slathered half. Top the chicken with a layer of tomato slices (seasoned with flaky sea salt and freshly ground black pepper) and a couple of handfuls of arugula. Finish by placing the mustard covered half on top and slicing crosswise into individual sandwiches.