Combine water, quinoa, cilantro, chili powder, cumin, garlic pepper, and salt in a saucepan and bring to a boil. Cook until water is absorbed, about 20 minutes.

Meanwhile, heat a large skillet over medium-high heat. Cook and stir beef in the hot skillet until browned and crumbly, 5 to 7 minutes. Set aside to cool slightly.

Preheat the oven to 450 degrees F (230 degrees C).

Rub coconut oil on the outside of the bell pepper halves. Place 1/4 slice of pepper Jack cheese inside each bell pepper half.

Add cooked beef, beans, and salsa to the saucepan with the cooked quinoa and stir thoroughly. Fill each bell pepper half with beef mixture and place on a baking sheet.

Bake in the preheated oven for about 30 minutes. Remove from the oven and place a 1/4 slice of pepper Jack cheese over each pepper. Return to the hot oven and bake until cheese is melted, about 5 minutes more.