Set oven to Broil. On a sheet pan lay out 20 saltine crackers salt side down. Using a knife spread tomato paste onto each cracker. On a microwave safe plate, heat the sausage links for approximately one minute, or until heated through. Carefully split sausages lengthwise making sure not to cut all the way through. Half the sausages and place them cut side down onto the crackers. Fold each slice of cheese in half and then in half again to make 4 equally sized squares. Place on top of sausage. Broil 2-5 minutes until cheese is melted making sure not to burn.