There is little doubt that Angus MacGyver could open a can without a can opener if he can defuse a nuclear bomb with a paper clip.
Grab the can with one hand while firmly holding the spoon in the palm of the other. Apply pressure as you move the utensil's tip back and forth along the can's rim, where the metal is the softest.
Locate a good knife (not a butter knife). The knife should be carefully placed upright with the blade pointing downward someplace around the can's rim where the metal is soft.
Find a rock, a flat piece of concrete, or something else rough. Press firmly against the rough object while rubbing the can's top against it.
Put the can on a solid surface and firmly grasp the hammer so that the claw is facing the can. The can's rim is the softest part of the metal, so use the hammer's claw to pierce it there.
Make a hole near the rim of the can's top with the end of a pair of needle-nose pliers, then keep going around the can's perimeter.
Asking your neighbor next door for a can opener, assuming you get along with them, would be preferable to slamming a can of beans with a hammer.