Rinse the amaranth thoroughly in a fine-mesh strainer under cold water to remove any bitter residue.
Heat the olive oil in a large skillet or paella pan over medium heat.
Add the diced onion and red bell pepper to the pan, sautéing for 4-5 minutes until the vegetables are softened and the onions are translucent.
Stir in the minced garlic, smoked paprika, and saffron threads, cooking for 1 minute until highly fragrant.
Add the dry amaranth to the skillet and toast for 2 minutes, stirring constantly to coat the grains in the oil and spices.
Pour in the chicken broth and bring the mixture to a boil. Reduce the heat to low, cover, and simmer for 15-18 minutes.
Once most of the liquid is absorbed but the amaranth is still slightly wet, nestle the Trader Joe's Seafood Blend and frozen peas into the grain mixture.
Cover and cook for an additional 5-7 minutes, or until the shrimp are pink and the scallops are opaque.
Remove from heat and let the paella sit, covered, for 5 minutes to allow the amaranth to finish absorbing the steam.
Season with sea salt and black pepper, then garnish with fresh parsley and serve with lemon wedges for squeezing over the top.