How to make chicken liver less explosive?
You have a few options to lower their explosiveness:


Pierce the skin, like you do before baking a potato.
Lower your frying temperature can help a bit, but you'll probably always need to use a temperature higher than the boiling point to get any kind of crisping action.
Dehydrate the liver a bit before frying. You could use a dehydrator, a low-and-slow oven bake or a low temperature, low oil sauté to get them to release their juices (like you do for browning some mushrooms). I don't know which of these will work best for liver, but naturally you'll lose a little bit of the final juiciness. 


You mention the splash guard, which I can't recommend enough. These numbers are cheap and easy to find.



But you can also protect your hands directly. I recommend something articulated, like this pair of silicon mold Storm Trooper styled oven mitts from Think Geek:



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