Let's start preparing the eggplants. Wash and cut eggplants into small cubes; put them in a pan and drizzle with olive oil, vinegar, salt, pepper and fresh thyme leaves. Cook them in the oven (200°C) until they become golden brown (15-20 minutes).
Let's now prepare the "Italian guacamole": blend avocado, garlic, onion, lemon juice, capers and tomatoes until you have a smooth cream. If you like you can add a little salt, but keep in mind that capers are quite salty. Put the guacamole into a bowl and keep it in the fridge.
When the eggplants are done take them out of the oven and let them cool down. Heat a large nonstick skillet and put piadinas on it, about 1 minute per side.
Now we are ready to fill our piadinas: spread some guacamole on it, sprinkle with roasted eggplants, add a few lettuce leaves. Close each piadina as you like and enjoy :P
Store guacamole leftovers in the fridge and use them for preparing a bruschetta, or pasta, or just try it with raw vegetable sticks for a really yummy appetizer.