Seafood salad thai-style (yam thale)

Ingredients

• 200 g white prawns
• 100 g shelled mussels
• 100 g squid
• 4 steamed crab sculls
• 10 hot chillies
• 5 cloves garlic
• 3 tablespoons lime juice
• 2 tablespoons fish sauce
• 1/2 cup Chinese celery, cut short
• 1/2 teaspoon sugar
• lettuce, onion
• Fresh vegetable for side dish