In a large skillet, heat olive oil over medium-high heat until shimmering. Add guanciale and pepper flakes and cook, stirring, until lightly browned, about 5 minutes.
Add wine and cook, scraping up any browned bits on the bottom of the pan, until nearly evaporated, about 3 minutes.
Add tomatoes and bring to a simmer. Season with salt and pepper.
Meanwhile, boil spaghetti in salted water until just shy of al dente, about 1 minute less than package recommends.
Using tongs, transfer pasta to the sauce along with ¼ cup pasta cooking water. Cook over high heat, stirring and tossing rapidly, until pasta is al dente and sauce has thickened and begins to coat the noodles.
Remove from heat, add Pecorino Romano, and stir rapidly to incorporate. Season to taste with more salt and pepper. Serve right away, passing more cheese at the table.