Set a large 1-gallon stock pot of water to a boil and add the kosher salt. Place the linguine in the pot and stir until the water returns to a boil. Cook the pasta until tender, but with a bit of resistance (al dente), about 12 minutes.
While the pasta cooks, prepare the sauce. Set a 12-inch saute pan over medium-high heat. Add the butter and olive oil to the pan. Once the butter has melted, season the chicken with 1/2 teaspoon of the salt and add the chicken to the pan. Sear the chicken until well browned on both sides, about 2 minutes. Remove from the pan and set aside. Add the onions and habaneros to the pan and saute until the onions are softened and lightly caramelized, about 4 to 5 minutes. Add the garlic to the pan and saute until fragrant, about 30 seconds. Add the cream, remaining 1 teaspoon of salt, and the chicken to the pan and bring to a boil. Cook the sauce until the cream is reduced by half, about 2 minutes. Add the tomatoes, linguine and the reserved cooking water to the pan and cook, tossing to incorporate for 3 to 5 minutes. Remove pan from the heat and add the green onions, Parmesan and parsley and toss to blend. Serve immediately.