In a large skillet over medium heat, saute the onion in the olive oil. When translucent, add the sausage and break apart with a fork into small crumbles. Add the rice and mix together until translucent. Then add the wine and allow to evaporate.
Lower the heat. Slowly add a ladle of broth and mix together until absorbed. Continue adding broth until all is absorbed, cooking for about 15 minutes. The rice should be creamy and al dente. Add the peas near the end of the process. Add the Parmigiano and serve immediately with some freshly ground black pepper.