Davad saw the Jedi across the Dune Sea, and made no attempt to mask his own presence.  He could go undetected if he wanted, even to a Jedi, unless they were actively looking for him.  But he had been alone for a long time now, and sought some sentient interaction, even if it was a fight.  

He stood at the top of a dune himself, looking out at the form.  The suns were to his left, so both would be easily visible to each other, and as soon as the Jedi sensed him, he was sure to come investigate.

Tatooine had its dangers, and there [i]was[/i] an Imperial presence here, but it was a wild planet, and there were large enough stretches of barren empty desert that it was easy to get lost in them, and that served one well when being lost was their desire.  

[b][i]Come on,[/i][/b] he thought at the form, bending his aimless anger toward what he took to be a Jedi, [b][i]Bring your foolish monk ideas my way.[/i][/b]