Preheat the oven to 450 degrees Fahrenheit. Wash and dry potatoes and then place in a steam bag and steam in microwave for 9 minutes or until potatoes are soft. You may have to make them in two batches depending on the size of your steamer bag. You can also use a steamer basket if you prefer that method. Let potatoes cool for about 3 minutes before smashing.
Oil a baking tray with 1 tablespoon olive oil. Place steamed potatoes on a baking tray and using paper towel smash down each potato. Spread the other tablespoon of oil on top of each smashed potato. Sprinkle with salt and pepper. Bake in oven 16-22 minutes or until potatoes are slightly browned. Remove from oven and let cool a few minutes.
To plate, lay on fresh spinach, smashed potatoes, Tonnino Tuna with Sundried Tomatoes and Basil and feta chunks. Serve immediately.