Heat oven to 350 degrees. Line a sheet pan with parchment paper. With a pastry brush, lightly brush the slices of baguette with olive oil. Lay each piece onto prepared sheet pan, season with salt and pepper. Bake in oven for about 5-7 minutes until golden.
Microwave asparagus in the bag: Make a small hole in the top of the bag. Cook on high for 2-2½ minutes. Carefully remove asparagus, letting heat escape first. Cut into 1-inch pieces.
To assemble: Place a small piece of salmon on top of the crostini, then two pieces of asparagus, and top with one small slice of Brie.
Garnish with fresh cracked pepper. Serve immediately.