Follow these easy steps to create your Chickpea Salad Sandwich:

1. Mash Chickpeas: In a mixing bowl, use a fork or potato masher to mash the chickpeas until they are mostly crushed but still have some texture.
2. Add Vegetables: Stir in the diced celery, red onion, bell pepper, cucumber, and parsley until evenly mixed.
3. Prepare Dressing: In a small bowl, combine the mayonnaise, Dijon mustard, lemon juice, salt, and pepper. Mix well.
4. Combine Mixtures: Add the dressing to the chickpea and vegetable mixture. Stir until everything is well-coated.
5. Taste and Adjust: Taste the salad and adjust the seasonings as necessary. You may want to add more lemon juice or seasoning based on your preference.
6. Assemble Sandwich: Spoon the chickpea salad onto a slice of whole-grain bread or inside a pita. If desired, add lettuce leaves, sliced avocado, or tomato.
7. Top It Off: Place another slice of bread on top or fold the pita.
8. Serve: Cut the sandwich in half if desired, and serve immediately, or refrigerate for later.