Creating your Chickpea Salad Sandwich is both straightforward and enjoyable. Follow these steps to assemble this delightful meal:

1. Prepare the Chickpeas: In a mixing bowl, mash the drained chickpeas lightly with a fork, leaving some chunks for texture.
2. Mix Vegetables: Add the red onion, celery, and bell pepper to the mashed chickpeas. Stir well to combine.
3. Prepare Dressing: In a separate small bowl, mix the mayo, lemon juice, Dijon mustard, salt, and pepper until smooth.
4. Combine Mixtures: Pour the dressing over the chickpea and vegetable mixture. Mix until all ingredients are well coated.
5. Adjust Seasoning: Taste the salad and adjust seasonings with more salt, pepper, or herbs, if desired.
6. Prepare Bread: Take slices of your desired bread and toast them lightly if you prefer a crunch in your sandwich.
7. Assemble Sandwich: Spoon the chickpea salad onto a slice of bread, and add lettuce leaves on top. Finish with another slice of bread.
8. Slice and Serve: Cut the sandwich in half and serve immediately. Enjoy your delicious Chickpea Salad Sandwich!