In a small pot, bring water and salt to a boil. Add the peas and cook 2 minutes. Drain immediately and reserve.
Bring a large pot of salted boiling water to a boil. Add the pasta and cook until al dente.
While the pasta is cooking, make the sauce: In a large, deep skillet, heat the olive oil on medium-high heat. Add the peas and sauté for a minute or until slightly softened. Add the garlic and red pepper flakes; cook only a minute, making sure the garlic does not burn. Lower the heat and add the broth, ricotta, lemon zest and salmon pieces, and mix to combine completely. Season with salt and pepper. Taste for seasoning.
When the pasta is cooked, drain, reserving 1 cup of cooking water. Add the pasta to the ricotta mixture. If it is too dry, add a bit of the pasta cooking water to moisten. Mix to combine. Cook for a minute on low heat. Taste for seasoning. Serve immediately.
Nutrition information per serving: