Preheat a grill or grill pan to medium-high heat. Drizzle the pineapple slices with olive oil, then season on both sides with 1 tsp Kosher salt. Grill. Let cool slightly, then cut pineapple rounds into a small dice.
Place the grilled pineapple in a large mixing bowl. Add cubed avocado, finely chopped jalapeño, red onion, lime juice (if using), chopped cilantro, extra virgin olive oil, and Kosher salt.
Stir well, then taste and adjust seasoning. Refrigerate until needed or serve immediately!