Preheat the oven to 400F (200C). Arrange the chicken on a sheet pan, drizzle with olive oil, and coat with the combined spices.
Roast for 20 to 25 minutes, until the internal temperature reaches 165F (74C), then rest briefly and slice into thin strips. For a grilling option, grill over medium-high heat to 165F (74C), rest, and slice.
Rinse the jasmine rice until the water runs mostly clear. Combine it with the chicken stock, bring to a boil, reduce to low, cover, and simmer for about 15 minutes, until the liquid is absorbed. Rest covered for 5 minutes, then fluff with a fork.
Combine the cucumbers, avocado, and lime juice, season with salt, and toss gently.
Heat olive oil in a skillet over medium-high heat and cook the peppers until softened and lightly charred.
Combine the corn, mayonnaise, and a little Tajin, stir until coated, and adjust the seasoning.
Divide the rice among bowls, top with chicken, salsa, peppers, and corn salad, and finish with pickled red onions and lime wedges if desired.