Preheat the oven to 400°F (205°C). Scrub the 4 large russet potatoes well, then dry them completely so the skins crisp well.
Place a baking sheet or a sheet of foil on the lower oven rack to catch any salt or drips.
Pierce the potatoes a few times with a fork. Use 1 tablespoon avocado oil to coat the potatoes, then rub the oiled skins with 1 tablespoon fine sea salt.
Place them directly on the center oven rack and bake for 1 hour 10 minutes to 1 hour 25 minutes, until the skins are crisp and the centers feel soft when pressed.
Warm the 1 (13.7oz.) can Heinz baked beans in tomatoes in a small saucepan over medium-low heat for 4 to 5 minutes, stirring occasionally.
Cut a cross into the top of each potato by making one slit lengthwise and one slit across the center. Press the sides inward to open the potatoes.
Add 1/2 tablespoon of butter to each potato, then season the insides with fine sea salt and ground black pepper. Fluff the centers with a fork.
Top each potato with some of the 1½ cups shredded white cheddar cheese, then spoon the hot baked beans over the top. Finish with the remaining cheese.
Scatter the fresh chives over the top and finish with additional salt and black pepper. Serve right away while the skins are still crisp.