Heat olive oil in a large skillet or paella pan over medium heat.
Add chopped onion and garlic, sauté until soft.
Stir in red bell pepper, green beans, and tomato. Cook for a few minutes.
Add paella rice and stir to coat the grains with oil.
Pour in vegetable broth, smoked paprika, and saffron threads. Stir well.
Bring to a boil, then reduce heat to low. Simmer uncovered for about 20 minutes, or until rice is tender and liquid is absorbed.
In the last 5 minutes of cooking, add peas on top. Do not stir.
Remove from heat and let it rest for a few minutes. Serve with lemon wedges.