Bring a large pot of salted water to a rolling boil over high heat. Add orzo pasta and cook for about 10 minutes until al dente. Drain and rinse under cold water.

In the same pot, bring fresh water to boil, and blanch green beans for 3-4 minutes. Transfer to ice water, then drain.

In a large bowl, combine the cooled orzo, cherry tomatoes, green beans, olives, and tuna, flaking the tuna into pieces.

Whisk olive oil, lemon juice, salt, and pepper in a small bowl until emulsified. Adjust seasoning as needed.

Pour dressing over the salad, toss gently, and serve immediately or chill for flavors to meld.