Cook the pasta according to the package instructions. Drain and set aside.

Meanwhile, season the salmon with salt and pepper and place it in a cold skillet. Add enough water to create a thin layer on the bottom of the skillet. Bring the water to a simmer over medium heat, then cover and steam for about 10 minutes. Add the frozen peas and more water if needed to maintain a gentle simmer. Cover and steam for 6-8 minutes longer, until the salmon is opaque and the peas are heated through.

Transfer the salmon and peas to the pasta. Add the butter and Italian seasoning, then season with salt and pepper. Toss gently, breaking the salmon into flakes as you mix. If the pasta seems dry, add a splash of water. Serve.