Agility training clubs train on either sand or grass. Slabs are not suitable at all. I would suggest that you invest in a good headcollar & muzzle & walk him. A bored dalmation will be going stir crazy. My GSD is not sociable on walks around his home territory. However, I go agility training & I attend agility shows. I also walk him twice a day, he is always on the lead when other dogs are close by, but I can't let his temperament stop me exercising him, that would not be fair. You need to get back to basics with him & start & give him the exercise & stimulation that a dalmation needs. You are the boss, you are in charge, not him.