Place the cucumber slices, cherry tomatoes, red onion, and cilantro in a large bowl.
Sprinkle the vegetables with kosher salt, black pepper, garlic granules, and dried oregano.
Drizzle the salad with olive oil and lemon juice. Gently toss to combine.
Serve immediately, or let rest at room temperature for 10 minutes to allow the flavors to meld. Gently toss again before serving.
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Notes
Don't skimp on the olive oil! It's what makes the salad so flavorful. I've seen recipes that add 1 or 2 tablespoons of it. I highly recommend using the full three tablespoons. It will make a big difference. And definitely use good olive oil in this recipe.
Make sure to slice the onions very thinly. No one wants to bite into a big chunk of sharp onion in their salad.
When you sprinkle the spices over the salad it might seem like a lot, but I do recommend using all of them. They make the salad very flavorful.
This is not a good recipe to make ahead of time. It's best enjoyed when freshly assembled or after a short rest for allowing the flavors to meld. But if you find yourself with some leftovers, they'll keep alright in the fridge, in an airtight container, until the next day. I wouldn't try to keep them beyond that.