Rinse quinoa under cold water, then combine with water in a saucepan and bring to a boil. Reduce heat, cover, and simmer for 15 minutes until fluffy. Fluff with a fork and set aside.

Season steak with salt and pepper. Preheat skillet over medium-high heat and cook steak for 4-5 minutes on each side for medium-rare. Let rest for 5 minutes, then slice thinly.

In the same skillet, heat olive oil and sauté bell peppers for 3 minutes. Add spinach and sauté until wilted, 1-2 minutes.

Layer quinoa, steak, sautéed vegetables, and cherry tomatoes in a bowl.

Drizzle with lemon juice and serve warm.