Authentic Greek and Latin Food Where?
There's a recent post about Greek restaurants. Most of them are in Astoria.
There's plenty of Latin American food in the Jackson Heights, Elmhurst and Corona area.
Colombian is the biggest group: La Pequeña Colombia on Roosevelt & 84th, Tierras Colombianas on Roosevelt between 82nd and 83rd, Pollos a la Brasa Mario on 37th Ave & 83rd or Roosevelt & 81st. Plus many more.
For Peruvian, I like Inti Raymi on 37th Ave between 86th and 87th. For chicken and fancy atmosphere, there's Pio Pio on Northern Blvd. between 83rd and 84th.
For Argentine: La Porteña on 37th Ave & 75th Street. Also several at Corona Ave and Junction Blvd. Also Uruguayan (very similar) El Chivito d'Oro on 37th Ave/84th St and La Fusta on Baxter across from Elmhurst Hospital ER, a block off Broadway.
There's also Ecuadorian all over, though I haven't found one I really like yet.
For Mexican, we have Taquería Coatzingo on Roosevelt near 76th and another on 82nd just south of Roosevelt. In Woodside, they also speak highly of De Mole.
If you want Brazilian, there are a bunch of places in Astoria. I've not been to the more authentic ones.