Tartines with octopus and pickled fennel from The Hog Island Book of Fish & Seafood: Culinary Treasu

Ingredients

• 1½ cups (360 ml) rice vinegar
• 2 teaspoons fennel seeds
• ¼ teaspoon crushed red pepper flakes, or to taste
• 1 tablespoon yellow mustard seeds
• 1 tablespoon fresh dill weed
• 1¼ pounds (570 g) fennel bulbs, trimmed
• Freshly ground black pepper
• Two 4-ounce (115-g) cans octopus, drained
• 4 thick slices crusty bread
• 1 tablespoon sugar
• 1 tablespoon kosher salt
• 1½ cups (360 ml) water