In a medium skillet, melt the sugar over high heat. Add the pistachios and cumin and stir until golden and fragrant, about 2 minutes. Scrape the nuts onto a sheet of parchment paper and let cool. Break up the nuts to separate.
In a large bowl, whisk the olive oil and vinegar and season with salt and pepper. Add the lettuce and toss to coat. Transfer to plates, sprinkle with the pistachios and cheese and serve.
The pistachios can be stored in an airtight container for up to 3 days.