Rinse and add the 2 handfuls of arugula lettuce into a salad bowl.
Cut in half, peel, and remove the 1/2 whole avocado seed. Chop the 1 cup of onion and 2 cups of cucumber.
Add half of the avocado, onion, and cucumber into a food processor followed by the 2 tbsp of olive oil, 1/2 tsp of black pepper, and 4 tbsp of lemon juice. Blend until smooth.
Add the rest of the cucumber and onions on top of the arugula lettuce. Then, add the dressing.
Finally, add the 1/8 tsp of red pepper flakes on top and enjoy!