Slice baguette pieces in half lengthwise. Scoop out about 3/4 of the bread from the top and bottom halves to create pockets; save scooped-out bread for another use, such as bread crumbs, if you like.
In a large bowl, toss together crab, shrimp, corn, onion, and bell pepper.
In a small bowl, whisk together parsley, olive oil, vinegar, salt, and pepper.
Pour dressing over crab and shrimp mixture and stir to evenly coat filling.
Fill bottom halves of baguettes with salad, dividing evenly, and set top halves on salad.
Note: Nutritional analysis is per sandwich.