Special equipment: a medium slow cooker (4 quarts) Place the onions in the bottom of the slow cooker insert and toss with 1 teaspoon of olive oil to coat. Sprinkle the cumin, smoked and sweet paprika, sugar and 1/2 teaspoon of salt on top of the onions and toss to coat the onions evenly. Lay the sliced peppers on top of the onions. Finally, top the peppers with the minced garlic and remaining salt and olive oil, tossing the pepper slices gently to coat.
Cover and cook on low heat for 2 to 4 hours (for firmer veggies) or 4 to 6 hours (for softer, soupier veggies), stirring once about an hour before the cooking time is completed. It may also be cooked on high for 1 to 2 hours (firmer) or 2 to 3 hours (softer). Stir in the lime juice just before serving.