Cut muffins in half horizontally and toast.
Cut avocado in half, remove seed and skin, scoop out the flesh into a bowl.
Add tuna, onion, parsley, sweet chilli sauce and mayonnaise.
Season to taste and mix well with a fork.
Place equal amounts of avocado/tuna mix onto all eight muffin halves.
Top with a slice of cheese and place under the grill until cheese is melted.
For extra spice add some fresh chilli to the tuna mix.
Serving Size 4