Combine the avocado and Olive oil in a bowl and mash until relatively smooth. Drain the chickpeas and mash them in as well, as finely as you wish. Dice the tomato and scallion and add to the mixture. If you do not have scallions a quarter of 1 onion would be great as well or even onion sprouts.
Season well with the salt and pepper to taste. Juice half of a lemon/lime and mix it in.
Toast your bread and construct the sandwich! You may add more veggies or seasonings like cilantro, oregano, etc.