Sausage Kebabs with Pepper Sauce

Here’s a whole meal on a single skewer: the meat (two types of sausage), the vegetables (onion and bell pepper), even the starch in the form of papas criollas—Colombia’s tiny, buttery Creole-style potatoes. It’s a thing of beauty, not to mention an object of pride for a Colombian grill mistress named Mariela Alian, who operates a pushcart grill on the edge of Cartagena’s open-air food market. You can eat the whole shebang off the skewer or as a sandwich with Lemon-Garlic Mayonnaise (