How to Make It
Place bell pepper, cilantro, shallot, vinegar, olive oil, paprika, garlic, chiles, oregano, and salt in a food processor; process until smooth. Reserve 1/2 cup of the marinade. Combine chicken and remaining marinade in a large bowl, and refrigerate for at least 1 hour and up to 3 hours.
Preheat a grill to medium-high (about 450°F), or heat a grill pan over medium-high, and brush grate with oil. Thread shishitos and chicken onto skewers. Grill, turning occasionally, until just cooked through, about 8 minutes. Transfer to a platter, and garnish with cilantro. Serve with reserved marinade.