Pierce the squash several times with a sharp knife to allow steam to escape during cooking. Microwave each squash on high until tender, about 5 minutes. Turn the squash after 3 minutes to ensure even cooking.
Place the squash on a cutting board and cut in half. Scrape the seeds out of the center of each half and discard the seeds. Remove the pulp of the squash and put it into a mixing bowl. Repeat with the other squash. There should be about 2 cups of pulp. Sprinkle squash with the brown sugar and add the olive oil. Mix until smooth. Set aside to cool slightly.
Divide the lettuce among 4 salad plates. Top each with 1/2 cup of the squash mixture, 1/2 tablespoon sunflower seeds and 1 teaspoon honey. Serve immediately.