The darker the poblano, the richer the flavor, which varies from mild to strong.
In a saucepan over medium heat, warm 1 tablespoon canola oil. Add onion and poblano chile; cook 4 minutes.
Transfer to a blender. Add 2 cups water, 1/4 cup each cilantro and parsley leaves; season with salt and pepper. Puree until smooth, 1 minute.
In same pan, heat remaining tablespoon oil and rice. Cook, stirring, until lightly toasted, about 2 minutes. Stir in puree. Bring to a boil; reduce heat. Cook, covered, until tender, 15 to 17 minutes.
Remove from heat; let stand 5 minutes. Fluff rice; stir in 1 tablespoon each chopped cilantro and parsley.