1. Mix greens together, place in bowl.
2. Place chopped onions in the middle of lettuce.
3. Cut avocado in half, score with paring knife, then scoop out. Place around the sides of the greens. Add salt and pepper to your liking. Drizzle balsamic vinegar on the onions only.
4. Drizzle olive oil on the greens. Sprinkle with Sunflower seeds. Toss and serve.