This salad brings together tender potatoes, crisp cucumbers, rich tuna and creamy yoghurt dressing in a way that feels both comforting and refreshingly bright, making it ideal for days when you want something satisfying without feeling weighed down. The gentle sweetness of sautéed red onion melts into the dressing, adding depth and warmth that contrasts beautifully with the cool crunch of cucumber and the clean flavour of Greek yoghurt. Grainy mustard and olive oil give the sauce a subtle sharpness and silkiness, turning simple pantry ingredients into a dressing that tastes like it belongs in a bistro rather than a home kitchen. Hard‑boiled eggs and spring onions add a finishing touch of richness and freshness, so every forkful offers a mix of textures and flavours that keep you interested from the first bite to the last. This recipe is written for someone who may never have made a composed salad before, guiding you calmly through each step so you understand not only what to do, but why it matters. You will learn how to cook potatoes so they stay firm yet tender, how to draw excess water from cucumbers to avoid a watery bowl, and how to balance seasoning so the salad tastes lively rather than flat. The ingredients are familiar and easy to find, yet the final dish feels special enough to serve to guests or bring to a gathering with confidence.