Place avocado half on a lettuce leaf, on each of 2 salad plates. Arrange tomato slices beside avocado. Drizzle Basil Dressing lightly over avocado and tomatoes; spoon any remaining dressing into hollow of avocado.
Sprinkle tomatoes with sprouts, onion, and sunflower seeds. Serve at once.
Basil Dressing: In a small bowl mix vinegar, lemon juice, salt, sugar, pepper, and basil. Using a whisk or fork, gradually beat in oil until well combined.Servings: