Scrape the refried beans into a 1-quart saucepan and set over low heat. Stir in water 1 tablespoon at a time until the beans loosen enough to spread easily.

Heat, stirring occasionally, for 5 minutes until warmed through. Cover and set aside off heat while you scramble the eggs.

Crack the eggs into a mixing bowl. Add the milk, salt, and pepper, then whisk until fully combined and slightly frothy.

Melt 1 tablespoon of the butter in a 10-inch nonstick skillet over medium-low heat, tilting to coat the pan.

Pour in the eggs. Let them sit undisturbed for 20 seconds, then stir slowly with a silicone spatula, pushing curds from the edges to the center.

Cook for 4 to 5 minutes total, stirring gently, until the eggs are just set but still look a little glossy and wet. Pull the pan off the heat immediately, they'll finish cooking in the residual warmth.

Wipe out the skillet and warm each tortilla over medium heat for 20 to 30 seconds per side until pliable and lightly spotted.

Spread about 3 tablespoons of warm refried beans down the center of each tortilla.

Top with a spoonful of scrambled eggs, then sprinkle with shredded cheddar while the eggs are still warm enough to melt it.

Add salsa and cilantro if using, fold the tacos closed, and serve immediately with lime wedges on the side.