Multiple opponents can be dealth with fairly nicely using melee attacks. Hit as many as you want and if you use multistrike and close combat you get +1TN per opponent and only -1 power. {edit: and they get no reach.}
By itself this isn't impressive, but throw in Mr.Shock Glove and its pretty disgusting.
Shock gloves eat another power, but you deal a 7S stun that they resist with 1/2 impact and then get stunned by for power minus 1/2 impact minus successes on a body(4) or willpower(4) test.
Or you can be a real pain in the ass and take kung-fu with multistrike and multistrike(polearm).
The uber cheese head will dikote a polearm for a str+4D attack.
At +1tn per opponent, Str+4D, and 2 reach they are at TN2, 3, 4, 5, etc to hit them and all they need to do IS hit them, which means tying them in combat.
Strength 6 human gets a 10D attack and I don't think people are going to be wanting to eat that kind of damage.
I'm sure you could get away with something less cheesy if you take a telescoping staff with a screw in spear tip which you can dikote and end up with a Str+5M attack because a spear is just as long as a staff and the telescoping staff has a conceal of 5.
Under a longcoat that's 7. Say you also wear a merlin coat and the conceal bonuses stack. That's now a conceal 10 weapon and I don't see any real problems with this other than having to spend a turn screwing in the spear head.
Another really pain in the ass thing you can do is use a rattan stick.
According to the CC only armor worn in the location you target for a called shot counts for damage resistance.
A rattan stick to the face is Str+1D due to flechette rules and +1DL for the called shot.
TN7 with say, 6 dice for the attack is doable and if you go all out for the combat pool you can get 12 dice and you're going to slap them silly.
Say strength 6, and that's a 7D stun attack with no armor.
Hell, you don't really need the rattan stick. You just need a martial art that gives you -2TN to called shot, which heron kung fu does just fine.
You can use herding on your turn and force them into a wall. +2TN to them, -1TN for you.
You call a shot. Its TN6-1 = TN5. Just slightly harder than a normal attack.
If you slap them in the face you get a StrS stun attack, so let's say you're also wearing Mr Shock Glove.
Str-1S stun + 7S stun without a hope for armor means they are probably unconscious and sizzling, or barring that, really messed up because they're probably at a serious stun wound and have taken +2 as part of a disorientation most likely.
That's +5TN for anything so if they want to run for it they're not going very far because you get a free melee attack. At this point you can basically blow a kiss at them and they'd fall over dead as they aren't defending themselves and you're still wearing a shock glove.
If you want to be a really mean person get at least plastic bone lacing, heron style kung fu, and hardliner gloves.
Str+3M stun, which we'll call 9M stun. You can 1/2 that to make it phys so depending on your GM ruling, its either 4M or 5M if you get the hardliner added in for good measure.
Call a shot and a 4S physical attack, maybe even staged to deadly still isn't pretty as they either need to make 6-8 successes or use up some of that precious combat pool.
If they attack you, they lose however many dice they used. If they run, its even less to resist with. Chances are you can pop them for a 4S and then a 9S stun and get them +6TN to everything.
Only cost you 7800 nuyen for the lacing and the gloves. Not too shabby.
Plus you can be a real shmuck and take off the glove and slap them...but then it'd probably be clubs skill so you'd have to default to the martial art at +2TN