Look at that man! ___ him?

The correct answer is "Do you know him?". The phrase "Look at that man!" is an exclamation, and the question that follows is a simple present tense question about knowledge. The structure "Do you know" is the standard way to form such a question in English. Options like "Are you knowing" and "Are you know" are grammatically incorrect. "Does you know" is also incorrect as "you" requires "do" not "does".