It is not recommended to microwave canned tuna in its original can. The can is made of metal, and microwaving metal can be dangerous as it can cause sparks and damage to the microwave.
If you want to heat canned tuna, it's better to remove it from the can and place it in a microwave-safe container. You can then microwave it for a short time until it reaches your desired temperature. Keep in mind that canned tuna is already cooked and ready to eat, so you only need to heat it if you prefer it warm.
Alternatively, you can mix the canned tuna with other ingredients to create a warm dish and then microwave the entire mixture in a microwave-safe container.
Always be cautious when using the microwave and follow proper safety guidelines to avoid accidents and ensure your food is heated safely.