Combine the oil, lemon juice, garlic, salt and pepper in a shaker jar. Set aside.
PREPARE THE SALAD:
Prepare the green beans by rinsing and snapping the ends. Place in a pan with a steamer basket and steam 8 to 10 minutes until almost tender. Rinse under cold water to stop the cooking process. Drain well.
To assemble the salad, place the lettuce on individual serving plates, followed by green beans, tuna, tomato, red onion, eggs and olives.
Shake the dressing jar well. Pour over the plated salads and serve.