It is not idiomatic English - unless you are talking about cooked apple as a substance.
What kinds of pie filling do you like?
Apple is good, but I like cherry best.
When speaking about the natural, uncooked fruit, we would always say
Apples/cherries/oranges are good.
In the UK, a person who makes an application for state benefits is called a 'claimant', because they are 'claiming' what they believe they are entitled to.
Your text is saying that the claimants (people who already receive state unemployment benefits) are being paid supplemental unemployment payments as well.
There is nothing omitted from the grammar - if ...
Short answer - they're almost the same, but if you're not sure, say "aware of how."
There are a few points:
Dropping the "of" is a bit more casual. So you'd be less likely to do it when writing.
On the other hand, "aware" is not the most casual word to begin with. If you say "Are you aware of...?" in speech, you're ...