Season salmon w/salt and pepper. Place each salmon filet on top of 2 slices of lemon and 1/4 of the asparagus in the center of one 12 x 12 piece of foil. Repeat with remaining 3 pieces of foil.
Mix together butter, Italian seasoning, and garlic. Divide between the 4 packets of salmon, placing dollops on top of the asparagus. Fold the ends together tightly, so juices stay inside. Bake at 400* for 20 minutes. (Can be grilled as well.)