Cook the pasta according to the package directions.
Meanwhile, pulse the peas in a food processor or blender until chopped but not pureed. Add ½ cup ricotta, salt, and pepper and pulse to combine.
Drain the pasta, reserving ⅓ cup of the pasta water, and return it to the pot. Add the peas and reserved pasta water and toss.
Divide the pasta among individual bowls. Top with the remaining ricotta, a sprinkle of chives, and a drizzle of oil.