Place the cubed potatoes in a pot and add just enough water to cover them. Sprinkle with some salt.
Bring to a boil over high heat. Lower the heat and simmer until the potatoes are tender, about 10 minutes. Remove from heat.
Drain and mash the potatoes. A potato ricer works great. Set aside.
In a skillet over medium heat, melt the butter. Add the onions and cook them, stirring constantly, until softened (about 5 minutes).
Stir the cream cheese, chives and onions into the mashed potatoes until the cream cheese is melted and combined. Season with salt and pepper.
To Fill the Pierogies:
Moisten the edges of a dumpling wrapper with water, using your finger. Spoon about 1 tablespoon of potato filling (depending on the size of the wrapper) onto the center. Try not to overfill them.
Fold in half and press the edges together to seal them tightly. Place onto a baking sheet lined with waxed paper.
Repeat with remaining dough wrappers and filling.
To Grill the Pierogies:
Preheat your grill to medium heat and then turn off half of the burners to get 2 heat zones: one side with indirect heat and the other with direct heat.
Brush both sides of the pierogies with the oil, so that they don’t stick to the grill. Place them onto the indirect-heat side of the grill (the area with no flame underneath). Close the grill and cook for 10 minutes.
Move the pierogies to the direct-heat side of the grill (where there is flame underneath) and cook for about 1 to 2 minutes per side or until the pierogies are golden and puffy on both sides.
Let cool for a few minutes as the filling will be hot. Serve with BBQ sauce and sour cream or desired condiments.