Dry the salmon with a paper towel and season with salt and pepper. Heat a skillet with 1 tablespoon grapeseed oil over medium-high heat, add the salmon and sear for 3 minutes on each side.
Meanwhile, in a separate pan, heat the remaining tablespoon grapeseed oil over medium heat and saute the garlic and shallots until translucent, about 1 minute. Add the cannellini beans and warm for 2 minutes. Add the spinach and wilt for 1 minute.
Remove the salmon from the hot pan, add the lemon juice, stock and capers and reduce to make a glaze, 3 to 5 minutes. Add the butter and emulsify, turning off the heat and mixing until all is incorporated. Season with salt and pepper and add the parsley.
On a plate, add the cannellini and spinach mix. Place the salmon on top and spoon the sauce over the salmon.