If my opponent uses Hidden Blade on my unit and I react with a Hidden Temporal Breach do I still draw 2 cards?

No — the opponent (Hidden Blade's controller) does not draw 2 cards.

Here's why: your hidden Temporal Breach resolves first. It banishes your unit, then plays it back to the same location — but per Rule 124, a card that changes zones to a non-board zone becomes a new object. So when Hidden Blade resolves, its original target is no longer at the battlefield (a fresh copy is there instead). It mistargets: the kill is ignored, and since the draw is a linked instruction to that kill (359.3.e.14.a), the draw is ignored too. Your unit survives and re-enters the battlefield; the opponent draws nothing.