Prepare your sandwich toppings by dicing your celery and pickle, mincing your dill and slicing your tomatoes and avocado.
Drain and rinse your chickpeas and add to a food processor. Pulse until you get the consistency you want. You can also mash with a fork or potato masher if you don't have a food processor.
Add your mashed chickpeas to a bowl along with your vegan mayo, garlic, dill, celery, pickle, mustard and black pepper. Mix this until the flavours are all evenly distributed.
Assemble your sandwich with a layer of chickpea tuna, kale, tomatoes and half an avocado.