Peel and section the grapefruit with a sharp knife and set the segments aside. Peel, remove the seed, and slice the avocado. Place the salad greens on a chilled plate then sprinkle with the sunflower seeds. Next, layer the avocado then grapefruit segments on top of the greens. Drizzle with desired amount of the honey mustard dressing.
I do not typically use store bought dressings but there are a few on the market that pass my "Mom label reading inspection." Briannas' Brand is one of my go-to dressings and their Honey Mustard is a wonderful pairing with this salad.