In a bowl, whisk together 8 large eggs, 4 tablespoons milk, and 1/2 teaspoon kosher salt until blended.
Heat a nonstick skillet over medium-low heat and add oil or butter to lightly coat the pan.
Pour the egg mixture into the skillet. Stir gently and continuously until the eggs are mostly set but still slightly moist, about 2 minutes.
Add 1 1/2 cups cooked pinto beans and 1 cup salsa to the eggs. Stir to combine and cook until the beans and salsa are heated through and the eggs are fully set, about 2 minutes.
Remove the skillet from the heat.
If desired, warm 4 tortillas until pliable (for example, 15–30 seconds per side in a dry skillet or 15–20 seconds in the microwave).
Divide the egg-and-bean mixture evenly among the 4 tortillas, roll each up into a burrito, and serve immediately.