Chop the crushed garlic with the salt and press it with the side of the knife until mashed. Scrape the garlic into a small bowl and stir in the chili powder, 2 tablespoons of lime juice and the mayonnaise.
In a large skillet, cook the bacon in 2 batches until crisp. Pour off the fat between each batch. Drain the bacon on paper towels.
While the bacon cooks, toast the bread. Slice the avocado and sprinkle the slices with a few drops of the lime juice.
Spread 1 side of each piece of toast with the spicy mayo. Arrange the avocado slices on 4 of the toasts, pressing them firmly against the mayo. Arrange the bacon, tomatoes and lettuce on the avocado slices. Top the sandwiches with the remaining toast. Cut the sandwiches in half on the diagonal and serve with the dill pickle spears.