How would you guys from a vipassana or experiential perspective define these two buddhist terms: ignorance (avijja or avidya) and sense of identity (sakkaya-ditthi)?

My two cents:

Ignorance = the inability to see the dualities inherent in moment to moment existence - or - not knowing that what we experience is made by mind to seem like there is a "self" and an "other"

Sense of Identity = a mind-created, impermanent illusion or duality that presents itself as I/me/mine - or - the mind created sense of a subject (self) against which objects (other) can be viewed and compared. Humans tend to believe the "self" is permanent.

The sense of idenity is a product of ignorance.

JMHO

In my mind, the sense of identity can always be tracked back to a feeling of responsibility.   The feeling of responsibility can always be tracked back to muscle tension in the physical body.