To make the fried green tomatoes:

Sprinkle the tomato slices generously on both sides with salt and pepper. Place the slices on a plate or baking sheet between paper towels to dry out for 10 minutes.

In a pie plate, mix 1/2 cup of the flour and 1 teaspoon of salt. In a second pie plate, whisk the egg and milk to blend. In a third plate, mix the cornmeal and remaining 1/4 cup of flour. Working with 1 slice at a time, dip the tomatoes into the flour to coat lightly, then into the egg mixture, and lastly, dip them into the cornmeal mixture and pat firmly to coat. Place the coated green tomato slices on a baking sheet or a plate lined with parchment paper. 

In a large frying pan, heat the oil over medium-high heat to about 375°F. Add 4 tomato slices. Cook for about 2 minutes per side, or until golden brown. Transfer the fried tomatoes to a paper towel-lined plate and sprinkle with salt. Repeat to cook the remaining tomatoes. (The oil will get increasingly darker, but will remain clean enough to cook 3 batches of tomatoes.) Cut the tomatoes in half, if desired.

To make the pimento mayonnaise:

In a small bowl, whisk the mayonnaise, bell pepper, pickle, mustard, lemon juice, and hot sauce, if using, to blend. Season with salt, pepper, and add more hot sauce, if desired.

To make the sandwiches and serve:

Cut the rolls in half crosswise to make a total of 4 equal-sized sandwiches. Spread the pimento mayonnaise over the cut sides of the rolls. On the bottom half of each roll, add the lettuce and onions, and then the fried tomatoes and bacon. Top with the other half of the rolls, and serve.