Scrub potatoes with vegetable brush under cold running water. Peel and thinly slice. Place in 3-quart saucepan and add cold water to cover. Over high heat, bring to boiling. Reduce heat to medium-high, cover and simmer until tender, about 8 minutes. Drain.
In large nonstick skillet over medium high heat, heat oil. Add onion, jalapeño pepper and cumin. Cook, stirring occasionally, until lightly browned, about 5 to 6 minutes. Stir in corn and cook 2 minutes. Remove from heat and stir in potatoes, beans, cilantro and salt.
Place tortillas on cutting board. Top half of each tortilla with 2 tablespoons of the cheese, ¼ of the potato mixture and 2 tablespoons of remaining cheese. Fold plain half of each tortilla over the filling to form a semi-circle. Repeat for remaining t tortillas.
Wipe out the skillet and heat over medium-heat. Add 2 quesadillas and cook, turning once, until browned, cheese has melted and filling is hot, about 5 to 6 minutes. Transfer to a cutting board and repeat with remaining 2 quesadillas. Cut each quesadilla in half and serve.