Drain the chickpeas well in a colander and rinse them under cold running water. Rinse the half cucumber and cut it into equal, bite-sized chunks. Crumble the feta into small pieces and slice the five olives into rings or halves.
Take a large bowl to mix the salad in. Combine the drained chickpeas, cucumber chunks, crumbled feta, and sliced olives. Toss everything gently together so that all the individual ingredients are well combined.
Pour the tablespoon of olive oil over the mixture in the bowl. Sprinkle the oregano over the top to season the whole dish. Toss the salad again thoroughly so the olive oil and herbs distribute evenly over the chickpeas and vegetables.
Divide the prepared salad among a plate or a shallow bowl. Serve the dish immediately at room temperature, or keep it covered in the refrigerator until ready to serve.