Start by preparing the cauliflower mash: steam the cauliflower florets in a steamer or in a small pot of boiling water until tender, about 8-10 minutes.
Meanwhile, trim the ends of the green beans and blanch them in boiling water for 3-4 minutes until tender-crisp, then drain and set aside.
Pat the salmon fillet dry with a paper towel, and season lightly with salt and pepper.
Heat a non-stick skillet over medium-high heat and add half the olive oil. Once shimmering, place the salmon fillet skin-side down and sear for about 4 minutes before flipping and cooking for an additional 3-4 minutes, depending on thickness, until cooked through.
In another small pan, heat the remaining olive oil over medium heat, add minced garlic from the 2 cloves, and sauté for about 30 seconds until fragrant. Toss in the blanched green beans to coat evenly with the garlic oil, cooking for another 2 minutes.
For the mash, transfer the steamed cauliflower into a blender or food processor. Blend until smooth, adding a pinch of salt, pepper, and a splash of water if needed for consistency.
Plate the seared salmon alongside a serving of garlic green beans and a generous scoop of cauliflower mash. Serve immediately.