Cook potatoes in salted boiling water until tender, about 20 minutes. Drain and cool. Once cool, quarter potatoes; set aside.
Grill onion slices over high heat until lightly caramelized.
In a skillet over medium heat, toast coriander and cumin seeds for about 1 minute or until fragrant. Add oregano; and continue to toast about 20 seconds, be careful to watch for burning. Immediately remove spices from heat, transfer toasted spices into large bowl.
In a large bowl with toasted spices, add oil, vinegar, salt and pepper and whisk together to blend. Add potatoes, onions, chiles, bacon and cilantro; toss lightly to coat.