You'll still want to vent outside - it's what you cook not the type of cooktop that requires venting - induction won't produce as much heat as gas but you'll still have smoke, grease and steam to vent. Recirculating hoods are fairly worthless particularly if you have the option to vent outside.

Trailrunner recommended Tradewind, who have been making residential hoods for over 50 years, but there are lots of good brands.

The Induction Site has a formula for figuring out cfms for maximum usage. You probably don't need as much as that equation says for a powerful induction cooktop as you would for the equivalent gas, but a stronger hood on a lower setting is supposed to do a better job than a lesser hood on high.

Don't forget make-up air. If your house is tightly sealed (when you need MUA to prevent your furnace from being dangerously affected), or if you live somewhere it gets really cold or humid, you'll probably want to talk to your HVAC pro about bringing in make-up air that has been heated, or dehumidified or cooled.

But, yes, it's best to have a real hood. There's a huge difference.

That said, if you must go without, I'd do it with induction more than any other.