Wrap the tofu in a paper towel to remove moisture.
Season the tofu with salt and pepper.
Cut the ciabatta bread in half.
Heat olive oil in a pan and grill the tofu until golden brown.
Lightly toast the inside of the ciabatta bread in the pan.
Place tofu, sliced tomatoes, lettuce, avocado, and mustard sauce between the bread.
Cover with the other piece of bread to complete the sandwich.