Make this "taco on a bun" as zesty as you want, depending on the salsa's kick.
Drain beans, reserving 1/4 cup of liquid in a small bowl, and rinse.
In a medium skillet, brown garlic and beef over moderate heat for approximately 5 minutes. Reduce heat to low and stir in chili powder, beans, liquid, and cumin (if desired); simmer for 3 minutes.
Hollow out the roll halves and toast lightly. Divide the shredded lettuce and the beef and bean mixture evenly among the bottom halves of the rolls; top each with 2 tablespoons of salsa and 1 tablespoon of cheddar cheese. Cover with top halves of rolls and serve.
How kids can help: Fill rolls with beef and bean mixture. Top with salsa, then with cheese; cover with top halves of rolls.