Salmon Burgers with Avocado, Quick Pickled Onion and Avocado Aioli

Ingredients

• ½ cup apple cider vinegar
• 1 tbsp caster sugar
• 1 small Spanish onion, thinly sliced into rings
• 1 tbsp olive oil
• 4 seeded buns, toasted
• ½ baby cos lettuce, leaves separated
• 1 small Lebanese cucumber, thinly sliced
• Mint leaves, to serve
• 1 ripe Shepard avocado, sliced into wedges
• 600 g skinless, boneless salmon fillets, coarsely diced
• 1 small egg white
• 2 tbsp hot sauce, such as Tabasco
• 1 spring onion, thinly sliced
• Finely grated rind of 1 lemon
• 1 ripe Shepard avocado, flesh scooped from the skin
• ¼ cup avocado oil
• Juice of 1 lemon
• 2 garlic cloves