Heat the Beans: Pour the canned refried beans into a microwave-safe bowl and stir in 3 tablespoons of water to reach a spreadable consistency, about 1-2 minutes in the microwave, stirring halfway through.
Cool Slightly: Let the beans cool for 1-2 minutes so they're warm but manageable for spreading.
Combine Sour Cream and Seasoning: In a separate bowl, mix together 2 cups of sour cream with the 1-ounce packet of taco seasoning until evenly combined, about 1 minute of stirring.
Layer the Beans: Spread the warm bean mixture as the first layer across the bottom of a shallow 9x13 inch baking dish or serving platter, creating an even base.
Add the Sour Cream Mix: Spread the seasoned sour cream mixture evenly over the beans, covering them completely, about ¼-inch thick.
Layer the Guacamole: Dollop and gently spread the premade guacamole over the sour cream layer, being careful not to mix the layers together.
Drain and Add Salsa: Strain the chunky salsa through a mesh strainer to remove excess liquid, then spread it as an even layer over the guacamole.
Add the Vegetables: Sprinkle the shredded lettuce over the salsa layer, followed by the shredded cheese, then scatter the well-drained black olives, chopped tomatoes, and sliced green onions on top in that order.