Do I need to cook smoked beef before eating? I bought some beef from the supermarket that said "smoked beef" on the label and nothing else. It was contained in the fridge, not the freezer section. I'm not sure how to prepare this for eating. I tried making a few slices and put it in the foreman for about 5 minutes. It turned out tough after about 30 minutes after grilling.

How do I prepare this and how long can I store this in the fridge?
What it looks like you have there is a Pastrami. Though not a particularly 'good' one, perhaps made from Eye of Round rather than brisket. It has been brined (soaked in a salt solution) in order to preserve the meat and then smoked (most likely to an internal temperature of 175°F (80°C)). This should make the meat 'completely safe' from food borne illnesses and is good to eat either cold (which I prefer) or hot (as in a Reuben sandwich). It is typically shaved (sliced very thin). 

It should be stored wrapped in a cold place (the fridge). It has a reasonable shelf life, you might check to see of there is a 'best by' date, beyond that it would be impossible to say 'how long it will last' as there are just too many unknowns.