Actually most CEOs get paid in both, with the primary portion of income coming from stock options. Your best bet would be to look at Yahoo Finance then they have a section within the company page called Insider Transactions. You can check out there and it will answer almost all of your questions.
As for Bill Gates he has recently sold a fair amount of money in my terms, but not his(in terms of billions)... Check out
MSFT: Insider Transactions for MICROSOFT CP - Yahoo! Finance
edit: Just looked at
BRK-A: Insider Transactions for BERKSHIRE HATH HLD A - Yahoo! Finance and noticed that Warren also had sales, but they're called dispositions. Investopedia defines it as another term for a sale of stock, but on the insider transactions it has it sold at $0 per share for any of Warren's transactions. Anyone else care to expand on that for me?