In a medium bowl, stir together crabmeat, onion, parsley, dill, salt, pepper, oil, vinegar, and ¼ cup ice water until combined. Cover and refrigerate for 6 to 8 hours for flavors to meld. Drain crab mixture well before using.
Divide arugula leaves among Toasted Crostini. Place crab mixture on top of arugula. Serve immediately.
Recipe by TeaTime Magazine at https://teatimemagazine.com/herbed-crab-canapes/