Well, Slow Travel is all about engaging with the local culture, trying local foods, and checking out local independently-owned shops and galleries in the less-touristy areas of your destination - and walking and cycling are a wonderful way to get a feeling for the place you're visiting and what makes it unique. Slow Travel is about connecting with the place you're visiting in a more meaningful, mindful way, rather than flying in and rushing around for 36 sleep-deprived hours to see all the sights before you must catch the flight home.
My favourite memories of a visit to New Orleans aren't of the tourist traps in the French Quarter and the fake Mardi Gras parades thrown for the benefit of conference attendees, but a day spent meandering through the residential neighborhoods and indie shopping districts along Magazine Street, and an evening in a soul-food bistro recommended by one of the shopkeepers I met. Before that day, I felt like a visitor; after that day, I felt like a guest.
If you're new to the idea of Slow Travel, I recommend the excellent Jorg & Olif blog's "So, How Do You Travel Slowly?" - it's an excellent primer on ways to plan your vacation with slow principles in mind.