In a medium bowl, thoroughly mash half the chickpeas with a fork until smooth. Add the remaining chickpeas, lemon juice, olive oil, bell pepper, onion, parsley, salt, and black pepper, and stir to combine.
Toast the bread in a toaster or toaster oven and spread the mixture onto 2 slices, top with fresh spinach or lettuce, and assemble the sandwiches with the remaining 2 slices of bread.
For a packed lunch:
Cut each sandwich in half, if desired, and pack them into lunch containers.
Keep the sandwich fresh by adding your choice of vegetables and fruit into separate compartments. Close the lid and pack the lunch container into a lunch bag with an ice pack.