Add sliced cherry tomatoes, cucumbers, chopped red onion, and olives to the bowl with the dressing, mixing the dressing thoroughly with the veggies. Let them marinate while the pasta is cooking. The tomatoes should release juices.
Add drained and rinsed spaghetti and crumbled feta cheese to the bowl with marinated veggies. Toss to combine.
Season with salt and pepper. Add more lemon juice, if desired.
