Blend all dressing ingredients in a blender till smooth. Set aside.
Heat the olive oil in a small saucepan over medium heat. Once it's shimmering, add the tempeh cubes. Cook for 2 minutes on each side, or until the cubes are evenly browned, adding a few splashes or sprays of tamari or Bragg's as you go. The tempeh will take about 7-8 minutes in total.
Mix the berries, spinach, onion, apple, and avocado together in a large mixing bowl. Add the cooked tempeh cubes and toasted seeds. Dress with as much vinaigrette as you like, and enjoy!
Notes
Dressing makes about 1 1/2 cups. It can be stored in an airtight container in the fridge for up to 1 week.Thinly sliced, raw red onion can be substituted for the pickled onions, if using.