Heat the oil over medium heat in a dutch oven or large heavy-bottomed pot. Add the red pepper, onion and jalapeno and saute until softened, about 5-10 mins.
Stir in the reserved beans, salsa, cumin and season generously with koser salt and pepper. Simmer until hot, about 15 mins. Thin with additional stock if necessary.
Top your black bean soup with tangy greek yogurt. It really complements the flavor of the soup and helps to cool down the spice. Sour cream is delicious too!