Get a work out in and work out your dog with some amazing and fun trails your puppy may love. There are three great dog friendly hiking trails in Fresno area, from my experience. All of these trails are predominantly or completely paved so easy on fido's paws and minimal risk of any rocks or stickers getting in the paws. Additionally these trails are well maintained and I have not seen broken glass on them to further help protect fido. They are wide enough so people can pass in two directions with dogs and still keep the dogs apart. Additionally they are near places where you can stop and get water along the way, just in case your dog needs a drink.
The first one is the Fresno Clovis Rail Trail. This is one of the 1,600 trails nation wide that was funded by the Rails to Trails Conservancy. Initially they used unused railroads paths to develop trails. They have since expanded their program.
The next is the Lewis S Eaton Trail. This is another multi-use trail. Similar to the Fresno Clovis Rail Trail in amenities and safety for Fido it boasts a multitude of areas next to the trail where one can park and get to the trail by walking only a few feet.
Last but certainly not least is the Old Town Trail. This has all the some amenities as the other trails. The drawback of this trail is that there are sections where you need to cross streets or go through a parking lot. Additionally there is a section where you pass near a school which can be challenging for dogs that are easily distracted.