I grew up with this one. Something my mom made here and there. I hope you guys like it.

Ingredients:

3-4 oz package of corn beef meat in thin slices.
Medium chopped onion
1 cup mayo (more if needed)
1 – 1  1/2 cups shredded cheddar cheese
Chopped black olives if you like them

Mix all together and place on crunchy crackers and heat in microwave or toaster oven.