Strain and rinse the chickpeas, then transfer them to a medium bowl.
Using a fork or a potato masher, smash the chickpeas into a chunky mixture. (Optional: You can also add the chickpeas to a food processor and pulse them a few times until a chunky mixture is formed, just be careful not to over-blend them as you don’t want the mixture too mushy.)
Once you’ve smashed the chickpeas, add the mayonnaise, yogurt, red onion, celery, parsley, dill, lemon juice, salt, and pepper to the bowl and fold the mixture together until well combined. Taste and adjust seasoning as needed.
Place a slice of bread on a cutting board, spread one side with the chickpea mixture, top with a few leaves of lettuce, and another slice of bread to make a sandwich.
Any leftover smashed chickpea salad can be stored in an airtight container in the fridge for up to 5 days.