Drain and rinse the fresh chickpeas if using canned, then mash them lightly with a fork or potato masher in a mixing bowl until mostly broken but still slightly textured.
1 cup fresh shelled chickpeas
Dice the celery stalk into small, uniform pieces and add to the mashed chickpeas, folding gently to combine.
1 stalk celery
Stir in the mustard, pickle juice, and a pinch of salt and pepper until well combined; the mixture should be creamy and evenly coated.
1 tablespoon mustard, 1 tablespoon pickle juice, to taste salt and pepper
Toast the bread slices until golden brown, then spread the chickpea mixture evenly over one slice.
2 slices bread or sandwich rolls
Place the second slice of toast on top to assemble the sandwich, pressing gently to set the filling.
2 slices bread or sandwich rolls
Cut the sandwich in half diagonally or into halves, then serve immediately or wrap for later.
