mix the beans with the chili powder, garlic, cumin, smoked paprika, and cayenne (if using)
pulse together in a food processor until beans are finely chopped
add flour, pulse 2-3 more times to combine
check the mixture, if it's very wet add a little more flour to bind it together
heat the oil in a frying pan over medium heat
when the oil is hot drop by dollops in the oil
cook 2-3 minutes
meanwhile make the Lemon Chipotle Sour Cream by mixing together the sour cream, lemon juice, chipotle powder
then turn the sliders carefully, and using a spatula press down gently to make a small slider patty
cook 2-3 more minutes
drain on paper towels while the other batch cooks
serve hot with slider buns, tomatoes, shredded lettuce and the Lemon Chipotle Sour Cream OR use assorted condiments, like aioli, mayonnaise, ketchup or taco sauce