Toast with Lemony Pea Mash

INGREDIENTS

• Freshly ground black pepper
• 2 tablespoons chopped fresh chives
• 2 cups shelled fresh peas (from about 2 pounds pods) or frozen peas, thawed
• 1 tablespoon finely chopped preserved lemon peel (from 1/2 preserved lemon), divided
• 12 slices country-style bread or ciabatta, toasted
• 1 garlic clove, quartered
• 1/4 cup fresh flat-leaf parsley leaves
• 1 tablespoon (or more) fresh lemon juice
• 1/4 teaspoon Aleppo pepper or crushed red pepper flakes plus more for serving
• 3 tablespoons extra-virgin olive oil, divided, plus more for toast
• Kosher salt