Spread a thin layer of cream cheese over each bagel half.
Arrange the bagel halves around the outer edge of a large board or platter.
Fold or ruffle the smoked salmon and pile it in loose waves across the center of the board.
Scatter the cucumber and red onion slices around the salmon.
Spoon the capers into a small cluster near the salmon.
Tuck lemon wedges and dill sprigs into the open spaces between the other ingredients.
Finish with a few cracks of black pepper over the salmon and serve immediately, letting guests build their own bagels.
Good to Know
Slice the cucumber and onion and portion the capers and dill the night before; assemble the board itself no more than an hour before guests arrive so the salmon stays glossy.