Bring a large pot of salted water to a boil and cook the brown rice penne according to package directions until al dente.
Reserve 0.25 cup of the pasta cooking water before draining the pasta.
Season the chicken breast with sea salt and black pepper.
Heat the olive oil in a large skillet over medium-high heat and sear the chicken until golden brown and cooked through, about 6 minutes per side.
Remove the chicken from the pan, let it rest for 3 minutes, then slice into thin strips.
In the same skillet, add the chopped ramps and minced garlic, sautéing for 2 minutes until softened and fragrant.
Reduce the heat to low and whisk in the Greek yogurt, lemon juice, and reserved pasta water until a smooth sauce forms.
Add the baby spinach to the skillet and stir until just wilted.
Return the cooked pasta and sliced chicken to the pan, tossing thoroughly to coat everything in the creamy sauce before serving.