Combine rice, water or broth, salt, and 1 tablespoon oil in a pot. Bring to a boil, then cover and reduce to a simmer. Cook for 40 minutes. Remove from heat. Let stand, uncovered, for 10 minutes.
While the rice is cooking, heat the remaining tablespoon oil in a pan. Add the garlic and slowly toast until golden brown. Add the baby spinach and cook until it wilts, about 2 to 4 minutes. Remove from the heat and squeeze in lemon juice.
When the rice is ready, stir in the cooked spinach and half of the pepitas. Serve in bowls, topped with sliced avocados and remaining pepitas.