In a small bowl, whisk together the olive oil, lime juice, chili powder, cumin, sea salt, black pepper, and minced garlic to create the marinade.
Place the peeled and deveined shrimp in a shallow dish and pour half of the marinade over them, tossing to coat evenly; let sit for 15 minutes.
Chop the red bell pepper and red onion into 1-inch chunks and toss them with the remaining marinade in a separate bowl.
Thread the marinated shrimp, peppers, and onions onto skewers, alternating between the protein and vegetables until all pieces are used.
Preheat a grill or grill pan over medium-high heat and lightly grease the surface with a small amount of oil to prevent sticking.
Grill the skewers for 2-3 minutes per side until the shrimp are pink and opaque and the vegetables have developed a light char.
Serve the hot skewers immediately over a bed of fluffy cooked quinoa for a complete and balanced meal.