Focus on what you are craving. Do you really want to eat two whole avocados? Are you craving kale? If you open a can of chickpeas will you eat half the can with a spoon? Build the salad around the one ingredient you really want to eat.
Salad Dressing. There is nothing wrong with purchased salad dressing but its really quite simple to make your own. My favorite version of salad dressing requires a dollap of mustard, some red wine vinegar, a splash of oil, and some herbs such as oregano. Shake it all up in jar. Adjust amounts to personal preference.