Mexican bean burgers with lime yogurt & salsa

INGREDIENTS

• 2 x 400g/14oz cans kidney beans , rinsed and drained
• 100g breadcrumbs
• 2 tsp mild chilli powder
• small bunch coriander , stalks and leaves chopped
• 1 egg
• 200g tub fresh salsa
• 150ml low-fat natural yogurt
• juice ½ lime
• 6 wholemeal burger buns , sliced avocado, sliced red onion and salad leaves, to serve