Preheat oven to 400°; slice lemon into thin rounds

Place 2 large pieces of foil on a sheet pan + oil the foil; divide asparagus onto one side of each then top with a fillet; spread each with 2-3 tbsp sauce, lemon slices, 1 tbsp oil + salt/pep; fold empty side of foil over ingredients; working from one end, tightly fold edges of foil creating a sealed half-moon shape; repeat with other foil

Bake 13-18 min until salmon is firm, opaque + cooked through

Open foil packs by cutting a slit through center (watch out for steam!) + divide between plates