Lets put it in a simple way
Where ever you are a "resident" of or you claim to be a resident of, you have to pay tax on your world income in that country. If you are an h1-b that means you are a resident of US, you will have to show all income etc. on your 1040 and if you also claim your residency of canada then you will take all your income (including US salary, all bank statements etc ) on your canadian T-1 (including any canadian income if any) , claim foreign tax for taxes paid in US and pay any tax (if remaining to Canada) .
There is no easy or clean way of doing things. There is only 1 right way of doing things . It does not matter whether you start a business in canada or not , if you do , you are taxable on your canadian business income in canada and also US (under foreign income ) ..