Well I haven't heard of someone's blood pressure going up after exercise but I wouldn't doubt it, However, yes your blood pressure can go way up if you have a history of blood pressure and you eat something that you are not supposed to eat. You can make it go up so high that it could cause you to have a seizure and it could be fatal so be careful.
Whether a person's blood pressure goes high after a meal depends on a few things. If the person is prone to high blood pressure and the food is salty, their pressure could go up. If a person excercises, a heart rate usually speeds up and depending on the person, their blood pressure could rise, as well.
Pressure changes with everything one does. It has to imagine standing up without pressure increasing. You would feel like your going to pass out. That's orthostatic hypotension. Pressure up with exercise.
Salt needs to be in the blood to cause hypertension. Immediately after you eat it wouldn't have an effect.