Firstly, the Arabic language is a Semitic language and the Spanish language is a Romance language, the two language families are not related to one another. Arabic and Spanish each use different phonemes and are rendered using a different alphabet. This means that speakers could not even remotely hope to find some sense of mutual intelligibility in conversation. Some words that share a common root might sound somewhat similar such as the Arabic "naranj" and the Spanish "naranja" which are both derived from the same Persian root, the etymology is shared with the English "orange." But other than isolated and infrequent, and frankly useless examples like that, no, there is no evidence to support that a speaker of one might have an easier time acquiring the other than a speaker of almost any other language.
To add, I can't be bothered to sift through the responses again, but someone mentioned that Maltese is also a Semitic language. While that is true, a fair portion of its vocabulary consists of loanwords from Romance languages as well as from English. This is not uncommon, it's estimated that fewer than 35% of Albanian words are native to the lexicon. Just thought I'd clear that up as Maltese is the only "Semitic" language that holds official status in the EU.