Cut the salmon into bite sized pieces and set aside.
Heat the oil in a large skillet over medium low heat. Once the oil is shimmering, add the onion. Saute for 2 - 3 minutes until the onion starts to soften, then add the garlic and ginger. Cook for another 1 - 2 minutes, stirring regularly.
Add the coconut milk, soy sauce and water. Bring the mixture to a simmer then add the salmon chunks and broccoli. Turn to low and cook uncovered for 8 - 10 minutes until the salmon is cooked and the broccoli is soft. Stir in the spinach and cook until wilted, another minute or so.
Serve the curry over cooked rice with garnishes of choice!