You cannot do this OOTB since rendition dimensions are not sorted as properties.
Technically could search for rendition nt:files, create a custom QueryBuilderFiltering predicate that pulls them into memory and determines their size and filters them in/out - but needless to say this would be very very bad for performance -- so don't do this!
Instead, I suggest creating a WF Process (assuming 6.x) that determines and writes rendition sizes as JCR Properties that you can then search over. There are main places you could put this data:
1) on the rendition [dam:Asset]/renditions/[nt:file]/[oak:resource] node - however this would require a custom mixin to allow you to put these custom properties - however you could apply them on each discrete rendition node.
2) under [dam:Asset]/metadata in some structure that holds the rendition dimensions, along w/ the rendition name.
Then make sure these new properties are indexed - and then use query builder to query on these derived rendition size properties.