Citizens of a large number of Non-EU countries (see the list here) can spend up to 90 days in Spain without a visa. If you are a citizen of a non-EU country that isn’t on the list, you can apply for a short-stay Shengen visa that allows you to stay in Spain (and to travel to the other 26 countries in the Shengen area) for 90 days.
It is best to apply for a Shengen visa at least a month before you travel to Gran Canaria. If you plan to spend longer than three months in Gran Canaria, you need a long term work and residence visa. You have to apply for this kind of visa from your home country via a Spanish consulate. See this article for a useful summary of the paperwork you need to apply for a work and residence visa. We advise you to check the exact requirements with your local Spanish Consulate as they will know exactly what documentation you need to provide and the exact requirements. See this useful summary of long-term visa types available for Spain.
Entrepreneurs can apply for a fast-track visa provided that they meet the requirements. The fast-track visa, which takes 10 days to process, also covers spouses, children under the age of 18, and elderly family members. Non-EU nationals can also get Spanish residency (and citizenship after 10 years) by investing the sum of €500,000 in property: The so-called Golden Visa. See this full list of the visa types available to non-EU nationals coming to Spain and Gran Canaria.