In our little tea sandwiches, cooked asparagus is layered with a mixture of poached salmon, horseradish, and nonfat sour cream over whole-grain bread.
Place water, onion, parsley, thyme, bay leaf, and peppercorns in a medium pan set over high heat; bring to a boil. Reduce heat to medium-low, add salmon, cover, and allow to simmer until the salmon is cooked through, about 8 minutes. Remove salmon from water; when cool enough to handle, flake salmon into small pieces, and transfer to a medium bowl. Add horseradish, sour cream, and salt; stir to combine. Set mixture aside.
Fill a large bowl with ice and water; set aside. Bring a wide, shallow pan of water to a simmer over medium heat. Add asparagus; let simmer until tender, about 3 minutes. Transfer to the ice bath; let cool. Transfer to a cutting board, and slice the asparagus in half lengthwise; set aside.
Assemble the sandwiches: Spread reserved horseradish-salmon mixture onto each slice of bread. Top half the slices with six asparagus-spear halves, then cover with the remaining slices of bread. Trim crusts, cut each sandwich into four triangles, and serve immediately.
The spread can be made an hour or two ahead and chilled; assemble sandwiches just before serving.