In Portugal, the best way for you to accomplish this goal would be to apply for a residence visa. In your specific case, either a D-2, a D-7 or a EU Blue Card are the most effective. The D-2 visa is meant for applicants who to come to Portugal to work, either for a certain entity (dependent work) or by creating his own job position (independent work - incorporating a self-owned company in national territory, for example). The D-7 visa is meant for entrepreneurs and applicants who already have an income from their country of origin and is specific to highly qualified job positions foreseen by the government. The EU Blue Card is a mix of a D-2 Visa for dependent work and the D-7 Visa; it is meant for applicants who get highly qualified job positions and are employed by a certain entity.
