In a small bowl, whisk the oil, 1/4 cup sugar, vinegar, onion, mustard and salt until sugar is completely dissolved; set aside.
Place pecans in a small heavy skillet. Cook over medium heat for 1-2 minutes until nuts are toasted. Sprinkle with remaining sugar. Cook and stir for 2-4 minutes or until sugar is melted. Spread on foil to cool. Break apart.
In a large serving bowl, combine the lettuce, strawberries, cheese, sunflower kernels and sugared pecans. Drizzle with vinaigrette; toss to coat.