Bring a large pot of lightly salted water to the boil. Add pasta and cook until al dente, about 8 to 10 minutes; drain. Transfer pasta into a large bowl and mix in 1 tablespoon olive oil; cover and refrigerate until cool.
Place lentils into a small saucepan, cover with water and bring to the boil. Cover and simmer over low heat until lentils are tender, about 15 to 20 minutes. Drain and set aside to cool.
Combine the remaining olive oil, vinegar and garlic in a small bowl.
Remove pasta from refrigerator; add lentils, oil mixture, olives, feta cheese, red onion, mint and dill; stir until thoroughly blended. Season to taste with salt and pepper. Cover and refrigerate for at least 2 hours.