Cook the rice and cool. I found it easiest to make up a batch of rice in the morning, put it in the fridge for the evening or a day or two later.
In a large bowl combine the cold rice, sunflower seeds, salad greens. Toss.
In a small bowl mix the vinaigrette, whisking to mix.
Pour vinaigrette over the salad and mix.
Add the grapes and ricotta salata, toss a bit and serve cold.