One of the not-so-secret secrets of dining in France is that there are great Lebanese, Vietnamese, and Senegalese restaurants and dining experiences. Ultimately, these can trace their roots back to foodways that emerged through French colonial history. Likewise, you can find fabulous Indonesian food in Amsterdam, and Lisbon has a terrific network of African cuisines.
But I've never really considered if Spain follows the same pattern. Is it possible to get great Mexican (REAL Mexican, not cheese-and-sauce heavy Tex-Mex), Peruvian, Argentinian, etc. dining experiences in Spain? If yes, does it filter outside of Madrid into other cities and regions? Barcelona, perhaps? Or even places like Zaragoza, Pamplona, and San Sebastian?