Preheat oven to 400 degrees F.

In a large bowl, mash 2 cans pinto beans. Stir in 3/4 cup salsa and garlic to make a pinto bean mixture.

In a separate bowl, combine 1/4 cup salsa, cilantro, remaining 1 can pinto beans, cumin, and tomatoes to make a salsa mixture.

Place 2 overlapping tortillas in a pie plate. Spread 3/4 cup pinto bean mixture over tortilla to within 1/2 inch of edge. Top with 1/4 cup cheese.

Cover with 2 more tortillas in the opposite direction. Spread with 2/3 cup salsa mixture and top with 1/4 cup cheese.

Repeat layering twice, alternating pinto bean mixture and salsa mixture.

Cover with remaining 1 tortilla, and spread with remaining pinto bean mixture, salsa mixture, and cheese.

Cover pie plate with aluminum foil and bake for approximately 40 minutes.

Remove from oven and cut into wedges. Serve with salsa and sour cream, if desired.