Place your bread slices in a toaster and toast until they reach your preferred level of crispness. For optimal texture contrast with the creamy avocado, aim for a medium-dark toast.
Cut the avocado in half, remove the pit, and scoop the flesh into a bowl. Add the lemon juice, a pinch of salt, and freshly ground black pepper. Mash to your preferred consistency.
Using a sharp knife, slice the tomato into thin rounds approximately ¼-inch thick. For maximum flavor, let the sliced tomatoes rest on a paper towel with a light sprinkle of salt for 2-3 minutes.
Spread the mashed avocado evenly across the toasted bread slices, creating a layer approximately ½-inch thick. Arrange the tomato slices on top, slightly overlapping for even coverage.
Drizzle with olive oil and sprinkle with red pepper flakes if desired. Finish with a final light sprinkle of sea salt and freshly ground black pepper.
Add your choice of garnishes—microgreens, everything bagel seasoning, or a sprinkle of feta cheese.