Ingredients:

Whole wheat bread
1/2 avocado
handful of spinach leaves
few slices of cucumber
salt and pepper to taste
red pepper flakes to taste
1/4 teaspoon lemon juice

In a small bowl mix the avocado, lemon juice and salt and pepper. Toast bread until golden brown. Layer spinach leaves, then avocado mixture, then cucumber slices. Sprinkle with red pepper flakes. 

This simple breakfast idea is endlessly customizable. Add additional toppings of your choice, such as smoked salmon, a poached egg, pico de gallo, sprouts, basil, tomato, or feta cheese.