Preheat the oven to 425°F.
Peel (if desired) and cut the sweet potato into 1-inch cubes. Trim the asparagus by snapping off the woody ends.
Toss the sweet potato cubes and asparagus in olive oil, salt, and pepper. Spread them evenly on a baking sheet.
Roast the vegetables in the oven for 20-25 minutes, stirring halfway through for even cooking.
While the vegetables roast, season the salmon fillet generously with salt and pepper.
Heat a non-stick skillet over medium-high heat. Once hot, sear the salmon fillet, skin-side down first if applicable, for about 4-5 minutes per side until a crispy crust forms and the salmon is nearly cooked through.
In a small bowl, mix the Greek yogurt with the minced garlic and the juice of half a lemon, adding a pinch of salt and pepper to create a light, tangy sauce.
Plate the seared salmon alongside the roasted sweet potatoes and asparagus, and drizzle or serve the lemon garlic yogurt sauce on the side.
Garnish with an extra squeeze of lemon if desired, and serve immediately.