Toss Portobello mushroom caps in 1 tablespoon olive oil and sprinkle with salt and pepper. Grill over Medium-High heat, turning once, until tender, about 15 minutes.
Slice mushrooms in half length-wise and toss in Portobello Mushroom Sauce.
Slice each Ciabatta Roll in half lengthwise. Fill each with 1 portobello mushroom, ¼ cup roasted red pepper strips, ½ cup arugula and crumbled goat cheese if desired. Top with additional sauce to taste and serve.