Slice the onion thinly. Mix 2 tablespoons of the mayonnaise and the sweet chili sauce together. Mix the drained canned tuna with 1 teaspoon of mayonnaise.
Spread the mayo-chili sauce combination on the bread.
Put the sliced onion and tuna on the toast.
Add the cheese, and cook the toast in an oven until the cheese melts.
Eat while hot.
Story Behind this Recipe
I had some sweet onions with chili mayonnaise once at an izakaya (Japanese gastropub) and it was delicious, so I recreated it and put it on toast. I added some cheese and tuna which both go well with onion too.
If you are using regular onions, put the slices in a bowl of water for 5 minutes. I recommend using lots of cheese too.