Pat the salmon fillet dry with paper towels and season both sides with the sea salt and black pepper.
In a small bowl, whisk together the Greek yogurt, chopped fresh dill, lemon juice, lemon zest, and minced garlic until the sauce is creamy.
Heat the olive oil in a non-stick or cast-iron skillet over medium-high heat until it begins to shimmer.
Place the salmon in the pan and sear for 4 to 5 minutes until the exterior is golden and crisp.
Flip the fillet carefully and continue cooking for 3 to 4 minutes until the salmon is opaque and flakes easily with a fork.
While the salmon is searing, steam the asparagus spears for 3 to 5 minutes until they are bright green and crisp-tender.
Transfer the salmon to a plate, spoon the chilled lemon-dill sauce over the top, and serve immediately with the steamed asparagus.