Place eggs in a pan cover with cold water and bring to a boil.

Cover pan and turn off heat. Let sit for 8 minutes.

Fill pan with cold water to stop cooking.

Peel eggs, roughly chop and place in a bowl.

Add mayonnaise, mustard, chives, salt and pepper.

Gently mix.

If mixture is too dry, slowly add a little more mayonnaise.

Garnish bread with arugula and place half the mixture on each sandwich.