The night before, place black beans in a quart-sized container or jar and fill with cold water. Cover and refrigerate overnight.
Drain black beans; place in heavy saucepan or dutch oven. Fill with water to within 2 inches of the top of the pot. Add bay leaf, salt, and dried chile.
Place over medium-high heat and bring to a simmer; reduce heat to medium-low, cover, and maintain a simmer, stirring occasionally, for approximately 40 to 50 minutes or until beans are tender but still al dente.
Drain well, reserving 1 cup of simmering liquid for later. Discard bay leaf and dried chile.
In a large skillet or wok, heat olive oil until hot and shimmering. Add onion, garlic, poblano and jalapeno and sauté for about 8 to 10 minutes or until beginning to soften.
Add chipotle and cumin and a generous pinch of salt.
Add drained black beans and toss to coat.
Add ¼ cup of reserved black bean liquid, simmering until liquid has mostly absorbed/evaporated. Continue adding liquid, ¼ cup at a time, stirring until water has mostly evaporated and beans are well coated.
Season to taste with lime juice and salt, as desired.
To assemble, spoon a bit of black bean mixture down the center of each tortilla. Top with cilantro, avocado, crumbled cheese and a drizzle of sour cream. Serve warm.
