Start with peeled hard-boiled eggs. Roughly chop eggs and use a fork to mash them together with salt, pepper, mayonnaise, and a dash of mustard, if desired. Add chopped celery and onion if you'd like. Mix all ingredients together and serve on lightly toasted bread or over a bed of greens.
In need of a little crunch? Spread a bit of mayonnaise on one bread slice, and arranged sliced cucumbers in an even layer over the bread before topping with egg salad.