In a medium bowl, combine tamari, maple syrup and extra virgin olive oil. Place tempeh strips into marinade and make sure they are nicely coated with the marinade. Let marinate for 15-20 minutes.
Place on a baking sheet and bake for 10 minutes. Remove from oven and flip tempeh and bake for another 10 minutes, for a total of 20 minutes. The tempeh should be crispy but not burned.
To assemble sammie, place a few strips on toasted bread with tomato, sliced avocado and lettuce. You'll likely have leftover tempeh, just save it for another sammie on another day!