Preheat the oven to 375 degrees. Drizzle a little olive oil on the bottom of a sheet pan (or spray it with cooking spray). Line salmon up in the center of the pan. If there's skin, place the skin side down. Place the asparagus on the around the outsides of the salmon. Drizzle olive oil onto the fish and asparagus. Squeeze some lemon juice over the salmon and asparagus. Sprinkle the salmon and asparagus with salt, pepper, garlic powder and dill to taste (I tend to be very liberal with the dill, because I love it). Place a lemon rounds onto each piece of fish. Bake for 15-20 minutes or until the internal temperature is 145 degrees and the asparagus is cooked through. Serve immediately with extra lemons on the side. Enjoy!