29er is a marketing name for some ETRTO/ISO 622mm (aka "700C") rims. In principle, any 622mm bead seat tire will mount on the rim. Narrow tires are not necessarily faster than wide tires; rolling resistance is more a function of sidewall construction than width. Fortunately, there is a wide selection of high performance 622mm tires to choose from, if you're willing to spend enough $$$.

N.B. there's no free lunch. Lower rolling resistance comes at the price of durability and puncture resistance. You makes yer choice and you pays yer money.