1. Slice cucumbers thick enough that they can hold some weight.
2. In a large bowl, add chickpeas and lemon juice. Mix well. Mash chickpeas with a potato masher or back of a spoon. They do not have to be fully mashed, just spreadable.
3. In another bowl mix tomatoes, onions, oregano, and salt.
4. Spread chickpea mixture onto cucumber slices using a spoon. Top with onion and tomato mixture and serve.