Crab Soup

Ingredients

• 1 (16-oz.) package thin bún (Vietnamese rice vermicelli)
• 10 live blue crabs (about 3 1⁄2 lbs.)
• 1⁄2 cup small dried shrimp
• 3 egg whites, beaten
• 5 tbsp. corn oil
• 5 scallions (green parts cut crosswise into thirds, white parts thinly sliced)
• 2 1⁄2 tbsp. paprika
• 1 tbsp. fine shrimp sauce, plus more for serving (optional)
• 1 tbsp. sugar
• 3 medium tomatoes, cored and each cut into 8 wedges
• 2 cups mung bean sprouts
• 1 cup loosely packed mint leaves
• 1 cup loosely packed purple perilla (called tía tô) or basil
• Asian chile sauce, preferably Sriracha, for serving