Smashed avocado with crispy chicken, pickled onions & tortillas

INGREDIENTS

• 2 large, very ripe avocados
• juice 1 lemon
• 8 seeded soft tortillas , or your favourite flatbreads, warmed
• small bunch coriander , to serve
• 1 large red onion , very thinly sliced
• 100ml red wine vinegar
• 4 tbsp caster sugar
• 4 skinless chicken breasts , each cut into 3-4 chunky strips
• 284ml pot buttermilk
• 85g polenta or cornmeal
• 85g plain flour
• 1 tbsp sesame seeds
• 1 tbsp sweet paprika
• ½ tsp cayenne pepper
• 2 pinches ground cinnamon
• 1 tsp garlic salt (or normal salt)
• sunflower oil , for shallow-frying