"Salve" means " be healthy" and "be healthy" was subsequently used for the meaning of "greeting". Therefore, no matter what "hello" meant originally before it became a greeting, today it is a greeting in the same manner as "salve" is
And the way you translate that greeting is irrelevant. Salve, Maria = Hail, Maria.... etc. But it could be also "Hello, Maria" / "Greetings, Maria" / "Good day, Maria" ... and so on and so forth.