So sexual assault is a tricky area, with lots of restrictions on what you can ask a complainant. Primarily this covers the complainants prior sexual activity (so, to be crude, defence can't argue that "well she's a slut who sleeps with lots of men so she must have consented this time"). This is covered in s, 276 of the Criminal Code.
That being said - if defence wants to try and argue "you're making this up to get money" - I think that would be allowed. Whether it would be a good strategy is a different idea (humbly, defence counsel on sexual assaults are often better off just trying to tease out inconsistencies and unreliability from the complainant, rather than a full on frontal assault of claiming they're lying).