Boil a large, salted pot of water for your pasta. Cook it al dente according to package directions.
Meanwhile, season the salmon with the garlic powder and salt & pepper.
Add the oil and butter to a skillet over medium-high heat. Once the pan is hot, sear the salmon for about 3 minutes/side, until lightly golden, then transfer it to a plate.
Reduce the heat to medium and stir in the garlic, tomatoes, wine, and Italian seasoning.
Cook, stirring occasionally, until the tomatoes start to lose their shape (about 5 minutes).
Add the spinach and salmon to the pan, and break the salmon up into bite size pieces using your spoon. Let it cook for another 3-5 minutes, or until the salmon is cooked through and the spinach has wilted.
Season with salt & pepper as needed. Toss with the drained pasta. If you want a little more liquid in the sauce, add a splash of the hot pasta water prior to draining it.