Drain the chickpeas and rinse them under cold running water. Cut the half cucumber lengthwise in half and dice the flesh into small cubes. Rinse the two tomatoes and cut them into small pieces as well. Peel the half red onion and mince it as finely as possible.
Place the drained chickpeas along with the cucumber cubes, tomato and red onion into a large mixing bowl. Squeeze the lemon and mix the juice with the two tablespoons of olive oil. Pour this dressing over the vegetables in the bowl and mix everything together well. Season the mixture generously with salt and pepper.
Finely chop the parsley and crumble the feta with your hands. Sprinkle the parsley and feta over the contents of the bowl. Toss everything once more gently, ensuring the ingredients are well distributed but the cheese remains intact.
Divide the chickpea salad among plates or transfer to a large serving dish. Serve immediately.