Disagree. I'm a salsa dancer in the USA and I'm heavily involved in the salsa scene. Everyone says "dance salsa;" we NEVER say "dance the salsa." That's probably something that non-dancers or people new to dancing it would say. But I've never even heard new people say that either. "Dance salsa" makes perfect sense and sounds more natural.
The phrase "dance salsa" does seem to be fairly common on the web. For example, "How To Dance Salsa For Beginners" https://thedancedojo.com/how-to-salsa-dance-for-beginners/
When aprender is followed by an infinitive, you have to add the "a" first. The linked page below has two lists of verbs: those that require "a" before a noun, and those that require "a" before an infinitive. You'll see that aprender is on the second list. https://www.lawlessspanish.com/grammar/verbs/verbs-with-a/
I've never heard a reference to "the Salsa" without it needing an article in English. It's possible to use salsa as a way to describe dancing without the article, for example, "I'm learning to Salsa" or "I want to Salsa" but not the way it is written as our answer. "Learning to dance Salsa" just sounds incomplete without the article. At least to me it does. Ayuda, por favor! Gracias!