I want to jar a bunch of fruits and vegetables for the bar at our restaurant. Do I have to use mason jars? which technique works best.

I wanted to use the jars with the rubber seal and the clamp but am not sure if it is a no no. also wanted to know if I need to boil the jars after I pack them or can just boil them and then pack and seal them

You are talking about Weck jars. There are a number of posts on this site about canning with Weck jars.

Are you planning to use the food in these jars? Or is it more decorative?

just decorative

Then you can follow any canning recipe and don't need to worry so much about it since the food won't be eaten. Since each fruit and each vegetable has different properties in terms of acidity and texture, check a good canning source for precise instructions. The Ball Blue Book is an inexpensive and classic resource.

The Weck jars are really expensive but beautiful and perfect for show. Check the URL above for directions.

The Bormioli jars are beautiful, too, and less expensive:http://www.amazon.com/s/?ie=UTF8&keywords=bormioli+canning+jars&tag=googhydr-20&index=aps&hvadid=5548072527&ref=pd_sl_5fj4wa2gen_e.

Since they are for show, don't bother canning them, just pickle the vegetables and pour alcohol on the fruit!