Don't go to Kappabashi-dori hungry. While the street is known as 'Kitchen Town', the focus is on all things used to create food, rather than on food itself.
You'll find the strip in Taitō Ward between Ueno and Asakusa. Get there by heading to Ueno Station, or catching the Ginza line to either Inaricho Station or Tawaramachi Station. Make sure you leave time to take a wander through neighbouring Asakusa and visit Sensō-ji temple.
The kitchen ware-focused area is really just the street itself, you won't find the teeming side streets you might expect if you've already been somewhere like Tsukiji. Kappabashi hondori is a useful one to know though, if you're looking for a meal, this is the place to head.
As well as shops selling everything you need to construct a meal, you'll find lots of shops that specialise in selling just one thing, from coffee accessories, to brushes (never pass up the opportunity to buy brushes in Japan!), to chopsticks, to fake food.
Yes, the fake food aka 'food samples' that you see set to lure you into Tokyo's restaurants can be bought here. But, before you get too excited about souvenirs, it's all pretty pricey. You might be able to pick up a few magnets, or perhaps a spaghetti-encrusted phone case, but you'll be dropping a few hundred dollars on a decent-sized dish. Which makes for an expensive gag gift.
Those phone cases though...
The 'sample food' shops are great fun, and the perfect way to lure your friends and family who don't get excited about buying kitchen accoutrements along. Unless you're on a serious hunt, you don't need to allow more than half a day to explore the strip. Time it towards the end of your trip so that you can stock up. Bring home the tamagoyaki pan, nabe pot or Tiger rice cooker of your dreams.