In a medium bowl, combine the ground chicken, egg white, sea salt, black pepper, garlic powder, and onion powder until well mixed.
Form the chicken mixture into one large, even patty roughly 1-inch thick.
Heat the extra virgin olive oil in a non-stick skillet over medium heat.
Place the chicken patty in the skillet and cook for 5 to 6 minutes per side, ensuring the internal temperature reaches 165°F and the surface is golden brown.
While the patty cooks, toast the sprouted grain bun in a toaster or on a dry corner of the skillet until lightly crisp.
Mash the avocado in a small bowl and spread it evenly onto the bottom half of the toasted bun.
Place the cooked chicken patty directly onto the avocado layer.
Top the patty with the tomato slice, romaine lettuce, and thinly sliced red onion.
Place the top half of the bun on the burger and serve immediately.