Well, no, it doesn't sound nice (appetizing) the way you describe it, sorry to say. I mean you could put everything on a sheet pan and cook it and with the cooking time for a salmon fillet, nothing will dry up, but I would cook things separately. Keeping everything to a minimum I would brush the salmon in EVOO and season and at this point I would also toss the cherry tomatoes in a little olive oil as well and they should just blister and into a 350 oven until cooked to your doneness, I like salmon medium rare. Quarter or slice the mushrooms and sautee in a combination of olive oil and butter, season with salt and pepper and when you have them cooked to your liking remove from the frying pan and add the spinach and a splash of lemon juice and minced garlic if you have and season with salt and pepper. This needs to be timed to the salmon for the most part. salmon should come out of the oven and covered just as you start to prepare the mushrooms. Like I said this is very basic but you can add any sauce or condiment you have.