Mix the ingredients for the spicy mayo. Spread on one side of each bread slice.
Toss the shrimp in what's left of the sriracha mayo.
Lightly toast the bread slices in a hot skillet.
Top the bread with shrimp and capers, then place the shrimp toasts under the broiler until golden.
Serve these spicy shrimp toasts as an easy appetizer with lemon wedges and a sprinkle of chopped parsley.