"I found the simplest solution to looking bigger" It basically means he found an easy way to look bigger. Simple = Easy Simplest = Easiest Solution = To solve or an Answer This is the way some people speak as we don't give it much thought, but just think of solution as the word 'answer'. "I found the simplest (easiest) answer to looking bigger." It's not the best english, but most people speak like this, and wouldn't think of it as a mistake unless you gave it much thought, as it's really not a mistake. If you get what i'm saying?

The boy wants to look bigger. Therefore, he views not being able to look bigger as a problem. Therefore, he is looking for a solution to his problem, and since his problem can be defined as "how to look bigger?", he is finding "a solution to looking bigger". In this case you can view "the problem" as would be used in mathematics - more like a question to be solved. Does this make sense?