The Utah Preppers Network did a good post on the jar sealing attachment that you can purchase for vacuum sealers. It allows you to vacuum seal jars of food to increase shelf life. It isn't an alternative to pressure canning but will work with things you would need access to regularly. Most people know that you can use vacuum sealers to seal food and prolong it's shelf life. They work great to preserve foods you have dehydrated, food that you want to freeze, or pretty much anything you want to seal.
You can also use the sealer to vacuum seal lots of non-food items. I've seen people vacuum seal pairs of jeans, shirts, and socks to compress their size to put in one's Bug Out Bag. Knine, one of the KPN contributors, posted a tip and said he vacuum seals rolls of toilet paper which makes them a lot smaller and easier to store. The possibilities are endless when using your vacuum sealer. Obviously they use electricity so unless you have a solar setup you won't be able to use them off grid but they're very handy and will benefit you while you are
In an emergency situation where you are cooking solely from your food storage getting the amounts of each ingredient correct would be extremely important. You don't want to use too much of one ingredient and risk running out of it sooner than others. If you build your food storage based on serving sizes getting these right to make your food storage last as long as you planned is a critical part. You don't want to be caught with no measuring cups and unable to get the amounts right for your food when cooking from your food storage. 
A knife sharpener is another kitchen gadget that a lot of people overlook. Instead of buying quality knives and keeping them sharp, people throw them away and buy new, or try to cut with a dull knife. There isn't much worse (in the cutting world) than trying to cut something up with a dull knife. A good knife sharpener is a great investment and something great for preppers to keep in the kitchen.
There are a lot of knife sharpeners out there and it's hard to decide which one to get. I like the 
A can opener is an essential kitchen gadget to keep around. For obvious reasons, they allow you to open cans easily. Regular can openers leave sharp edges and once opened the cannot be closed back. The contents of the can must be eaten before they go bad. Enter in the smooth edge can opener. The smooth edge can opener opens the can from the side, creating a smooth edge that isn't sharp, and creates a lid that can be added back onto the top of the can for a nearly perfect seal.
The Oxo Can Opener is a necessary item in your food storage. A lot of times you're not going to eat the whole can of food after you open it, so with a smooth edge opener you can put the lid back on the can and save the food for later. This works great if you purchased a large bulk can of something and need it to last a few days. Even with the lid back on and sealed the food won't last forever, make sure to eat it within the next few days as quick as possible. This is why it's good to purchase smaller portioned canned goods to lower the risk of having to throw out food. In a survival situation, throwing out food is a huge no-no. 
Most people have a fully stocked kitchen with the tools they need to cook nearly anything. But it still seems that people overlook some of the simplest things to keep around. A funnel set is one of these overlooked items. Funnels come in handy a lot and help keep things clean and prevent spills. If you're transferring liquid from bottle to bottle always use a funnel. It's faster and a lot cleaner.