Put the rice in a pot with 2 cups water. Bring to a boil and cook until done, 15 to 20 minutes.
Heat the olive oil in a medium pan, and then add the pancetta and onions and saute until crispy, about 8 minutes. Add the peas and saute for 1 minute. Set aside.
Transfer the rice to a large mixing bowl and stir in the peas, pancetta and onions. Stir in the ricotta cheese and salt and pepper to taste and garnish with the pecorino cheese.