Boiling water without burning it

I have discovered that I like this simple openface sardine sandwich moderately well.

Ingredients
2 slices of bread
1 tin of sardines packed in olive oil
A little lemon juice

Instructions
Toast two slices of bread.
Open tin of sardines, remove sardines with fork and put them on the toast.
Split sardines down the middle so they're closer to flat, and arrange them on the slices of toast.
Put a little lemon juice in a spoon (so as not to accidentally pour too much onto the food) and drizzle it over the sardines.

I don't love it, but I like it well enough that it's a convenient quick meal, especially when trying to avoid dairy and non-fish meat.

Any other suggestions for quick and simple things that can be done with sardines, or minimal-effort ways this simple sandwich could be varied?