I usually like walking earlier in the day, and not after eating a lot. If I just had a big meal, I generally just feel the need to sit for a while. If I feel the need to exercise at night, I usually do pilates then instead of walking (and I wait a good bit after dinner)
We only take walks after dinner if there's going to be a pretty sunset. We had a beautiful sunset two nights ago! I don't really know how far we usually walk, most of the time it's about an hour's duration.