Warm a small non-stick skillet over medium heat and add the sunflower seeds. Toast the seeds while stirring constantly until lightly golden, about 3 to 5 minutes.
In a serving bowl, combine the spinach, berries, crumbled goat cheese, and sunflower seeds.
In a small bowl, whisk together the vinaigrette ingredients until well combined. Add salt and pepper to taste.
Just before serving, drizzle enough vinaigrette to lightly coat the leaves and gently toss. Serve immediately.