Get Ready: First, drain all the water or oil from your can of tuna.

Chop It Up: Take the cucumber and red onion and chop them into small pieces. Keep them small!

Mix the Cream: Cut the avocado in half. Take out the flesh and put it in a bowl. Use a fork to mash it up until it's super creamy.

Put it Together: Add the drained tuna, the chopped cucumber, and the chopped red onion to the bowl with the avocado.

Stir Well: Give it all a good stir. Mix everything until it looks like that creamy green spread in the picture.

Season It: Sprinkle some salt and pepper in the bowl. Stir again and taste it. Does it need more?

Serve It Up: Lightly toast your bread. Spoon the tuna and avocado mix onto the bread. Done! That's your easy, healthy sandwich!