Measure out 1 cup of dry orzo into a medium-sized sauce pan. Add 2 cups water. Set to boil on medium heat. Stir intermittently so pasta does not stick to the bottom of the pan.
While orzo is cooking, chop the poblano, green onion and spinach. For the spinach, I grab a large handful and do a rough chop. It doesn't need to be perfectly chopped into tiny pieces.
Add 1 tbsp olive oil to a medium-sized saute pan. Add the poblano and stir a bit so the oil gets all over the poblano. Saute until the poblano is soft and a bit blackened. You don't need to babysit it, but you do want to stir intermittently so it does not burn. (Poblano gets quite smoky when sauteed, and it releases capsaicin. If this bothers you, you can always microwave it to soften it.)
Into a large bowl, add the 3/4 cup green onion, 1 cup spinach, and sauteed poblano.
In a small bowl, add the 3 oz of lemon juice and 1/2 cup mayonnaise. Whisk together until incorporated. It may be a bit lumpy, but it should smooth out as you continue to whisk vigorously. (Feel free to add the ingredients to a food processor and make the aioli this way. It will result in a smoother sauce.) You won't notice this so much once you add the garlic. Add the 2-3 cloves of pressed garlic and stir to incorporate.
Once the orzo is done cooking, drain any remaining water, then stir in a bit of butter or olive oil to keep the pasta from sticking together. Transfer into the large mixing bowl with the poblano, green onion and spinach. Add 1 cup of feta cheese and stir to incorporate everything.
Add the lemon garlic aioli and stir until the sauce is incorporated into the pasta salad. Chill for at least 60 minutes before serving.