Rinse and strain the chickpeas. Place them in a bowl then smash them with a spoon.
Tear the dill off the stalks first and pull them into smaller pieces if they are bunched.
Add the onion, dill, mayo, vinegar, mustard and salt & pepper to the bowl. Mix well.
Toast the bread. Add the lettuce, then the chickpea salad. Top with tomatoes and pickles.
Notes
This will keep well in the fridge for 2 days.If you aren't vegan you can use regular mayo in the same portions.For a healthier option, smash a small ripe avocado and substitute it for the mayo.You can add celery to this but I find it overpowering.