Drain and rinse your chickpeas and add to a mixing bowl. Roughly mash.
Mix in the red onion, celery, garlic powder, sea salt, pepper, vegan mayo, and buffalo sauce. Mix until fully combined.
Assemble your open faced sandwiches! Toast your bread and top with a few avocado slices (use a fork to spread the avocado), spinach leaves, tomato slices, pickles slices, the chickpea buffalo mash, and a drizzle of vegan ranch.