Are you not really feeling the sparks yet? Usually there is some form of attraction that would make you want to kiss him because there is a click between the two of you. If you need to kiss him first to find out whether or not you like him, then you don't generally like him as much.
If you feel the spark, just lean superb close to his side, and then gently move your lip to his lip but let him kiss you. He should obviously get the sign if he's not blind lol
First and foremost, we don't know who "he" is. I presume it's a guy you recently started dating. Since you're in your mid to late 20's, I'm sure you're mature enough to know if you're actually interested in a guy. Why do you need to wait until he kisses you to make up your mind about him?