Your local Codes & HR will have the answer you are looking for.
Old Codes and some places still only require hoods over 'gas' cooking equipment to vent combustion gasses out of the kitchen.
Newer Code require hoods over 'gas & electric' cooking equipment to vent combustion gasses, smoke, and grease vapors produced by commercial cooking equipment.
Many new kitchens will also use the hood to vent heat out, even if the a hood was not otherwise required in an attempt to keep the kitchen cooler.
Generally, hoods are not required over small electrical appliances like a panini grills, electric sandwich grills, food warmers, and steam tables, ect. ... So yes it is possible to get by without a hood with all electric small appliance setup like a sandwich deli.
So what is your menu and what cooking & specific equipment will be required for your kitchen and service? This is what will determine if a hood must be installed to meet a Code.
Soup itself does not require a hood. It can be prepared in large crook pots or in a steam table. However, it is not likely your HR will allow soup to be prepared off premise except at an approved commissary.
<message edited by edwmax on Tue, 08/7/12 4:53 PM>