_Remove any broken beans or debris from the black beans. Place beans in mixing bowl and add baking soda. Cover with water 8 cm above level of beans and soak for 12–24 hours.
_Rinse and drain beans. Add beans and kombu to pot and cover with water 2.5 cm above beans. Bring to a boil and then reduce heat to simmer. Skim off foam. Cook until beans are tender but not mushy, approximately 40 minutes. Add water as needed to maintain water level.
_While beans are cooking, fry bacon to render fat. Save some bacon to chop and sprinkle on quesadillas, reserve the remaining portion for other uses. Strain fat through a fine strainer. Pour fat and onion into the frying pan and cook until soft, but do not brown. When beans are finished cooking, drain and add to pan with onion, cumin and bacon fat. Cook on medium heat and then transfer to a bowl and blend into a paste. Reserve and set aside.
_Coat pan with sesame oil and cook kimchi until warm and most liquid has evaporated. Place in bowl and set aside. Wipe out pan before adding just enough sesame oil to lightly coat.
_Set tortillas out to assemble quesadillas. Spread a thin layer of black bean paste on each tortilla. Distribute kimchi over tortillas and top with cheddar. Fold tortilla in half and add to pan on burner set to medium heat. Cook each side approximately 3–4 minutes until cheese is melted.
_Remove quesadilla and cut each tortilla into wedges. Top each wedge with sour cream or crème fraiche, a sprinkling of sesame seeds, a drizzle of sesame oil and, optionally, some of the chopped bacon.