In a medium-size nonstick pan, over medium heat, cook the eggs sunnyside up for about 3 minutes, or until the whites are mostly set, with some still-runny whites near the yolks. Season with pepper.
In a small bowl, mash together the avocado, lemon juice, and red pepper flakes.
Top the toasted bread with the avocado mixture and 4 tomato halves per slice. Top with the egg and serve immediately.