Scallop, avocado and mango tostada

Ingredients

• 2 ripe avocados, halved
• 1/4 teaspoon lime zest
• 1 tablespoon fresh lime juice
• 1/2 teaspoon salt, divided
• 1/4 teaspoon ground cumin
• 1/8 teaspoon paprika
• Generous pinch of cayenne pepper
• 12 large scallops, cut in half
• 1 mango finely diced
• 1 tablespoon vegetable oil
• 24 large tortilla chips