- Make the vinaigrette ahead by whisking together the lemon juice, vinegar, garlic Dijon mustard, and salt and pepper in a small bowl. Slowly whisk in the olive oil to blend. Set aside (can make a double batch to keep on hand!)
- Steam the potatoes in about 1 inch of simmering water for about 15 minutes until tender. Cool slightly and transfer to a large salad bowl, then season with salt and pepper. Add the tuna and while still slightly warm, whisk in ¼ cup of dressing.
- Bring a pot of well-salted water to a boil and add the green beans to the water, cooking for about 4 minutes. Immediately plunge the beans into a bowl filled with ice and water to arrest cooking. Drain and dry on paper towels. Add the beans to the salad bowl with carrots, if using and ½ of the chopped herbs, tossing with another ¼ cup of dressing.
- Pile onto a platter or shallow, wide salad bowl, and garnish with sliced eggs and tomatoes. Sprinkle remaining herbs on top.
Note: this dish is so versatile – use whatever vegetables you prefer and/or your preferred tuna. It is packed with healthy ingredients and protein and is fabulous with the Buffalo!