There really are a million ways out of a same-side grab. Cuong Nhu requires that you learn a new one for each promotion (at least in the beginning). My favorite is a soft-style method: leaving your wrist as still as possible, use your shoulder and elbow to rotate your elbow over his arm; drive your elbow down on the inside of his arm, breaking his grip and trapping his hand under your arm. You should be moving in close and have plenty of opportunity to knee him if necessary. I like this because it doesn't take much strength, and you can make that step in to him look submissive and take him unawares. However, this is difficult on someone much taller than yourself. The keys to weakening such a grip have already been mentioned: 1) distraction, and 2) get him to pull your hand into his body. Also, feel free to grab his wrist right back to help you maintain your balance while you kick the bleep outta him. But mostly, stay away from this guy, and file charges if he touches you unprovoked.