Cucumber and Avocado Salad Bean Dip

Name: Cucumber and Avocado Salad Bean Dip
Ingredients: 1 medium cucumber, coarsely chopped; 1 small red onion, chopped; 3 radishes, trimmed, thinly sliced; 1 jalapeño, thinly sliced; ⅓ cup fresh lime juice; 4 Tbsp. extra-virgin olive oil, divided; Kosher salt; 2 garlic cloves, coarsely chopped; 1 15.4–16-oz. can refried beans; ½ tsp. ground cumin; 2 Tbsp. unsalted butter; 1 Tbsp. hot sauce (such as Tabasco); 1 avocado, thinly sliced; 4 oz. queso fresco, crumbled; Cilantro leaves with tender stems (for serving; optional); Freshly ground pepper; Tostadas (for serving)